Weather Stations and Weather Forecasts: Can You Do It Yourself?

Background Information for Teachers

Meteorologists are scientists who study the layer of gasses surrounding Earth, called the atmosphere. The atmosphere is about 300 miles thick, and most of it is within 10 miles of Earth's surface. The weather is the reflection of what happens in this layer of air. Meteorologists help predict the weather by studying what happens in the atmosphere, more precisely, they follow changes in the air pressure, temperature, humidity, wind velocity, wind direction, etc., and apply physical and mathematical relationships to this information. They use weather connections (weather phenomena that frequently occur together) observed in the past to help predict the future. They also use weather patterns. A weather pattern is the repetition of the same type of weather on consecutive days. This works because the weather tends to repeat itself until something interrupts the pattern. For example, it can be clear and sunny for five consecutive days until a cold front brings a few days of cold, gloomy, and wet weather. A typical weather forecast is shown in Figure 1. Although these forecasts are often accurate, they remain educated guesses; these predictions are not guaranteed to occur.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies

A five-day weather forecast for San Francisco, CA during a week in August. The list has columns that describe the weather conditions, high and low temperatures, chance of precipitation as a percentage, wind direction/speed and humidity as a percentage for each day.

Figure 1. Five-day weather forecast for San Francisco.

Meteorologists collect a huge amount of data and use supercomputers to make their predictions. However, people have been predicting the weather for centuries without computers, and your class can too! With a knowledge of weather connections, one just needs to observe the current weather to be able to predict the future weather. Although these predictions are only valid for the near future, it is still exciting to be able to forecast the weather and it is a valuable skill to learn.

In this lesson, students collect weather-related data over a certain period of time. They set up a weather station to measure quantitative variables like temperature, precipitation, wind speed, etc., and collect qualitative data like cloud coverage. Students then graph their data and are challenged to confirm weather connections using their data. Finally, they use these connections to predict the weather.

Below is a list of weather-related variables with an indication of some global weather connections that are related to that variable. Notice that this is not an exhaustive list, and you might also find connections that are specific to your area.

Air pressure*, or how hard the air is pressing down on the Earth:

• Low air pressure indicates a change in the weather pattern.
• High air pressure indicates nice stable weather for the next 12 hours.

Sky coverage*:

• Clear skies allow for bigger temperature changes between day and night. This happens because clouds reduce the passage of light and heat.
• White flat clouds (e.g. cirrocumulus clouds) high in the sky, as shown in Figure 2, mean stable air. The weather will stay as it is.
• Fluffy clouds (e.g. cumulus clouds) indicate that the air inside the cloud is rising. When these clouds are surrounded by blue sky, the weather will be fine in the coming hours. They can also grow into thunderstorm clouds. In that case, a storm is brewing.
• Thunderstorm clouds (cumulonimbus cloud) are huge towering clouds. They can be white at first but grow darker as time passes. These clouds bring thunderstorms. The darker the cloud, the sooner the storm will hit.
• Dark, low hanging clouds that cover the sky (nimbostratus) indicate a storm is close. Notice that normal wind patterns can drop just before a storm hits.
• Gathering, darkening clouds, as shown in Figure 3, indicate bad weather is coming. Dispersing and/or lifting clouds mean the weather is clearing out.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies
Figure 2. High clouds predict stable weather.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies
Figure 3. Gathering and darkening clouds predict rain.

Relative humidity* (often referred to as humidity):

• The relative humidity usually drops when the air heats up and rises when the air cools. This is why evenings and mornings can be damp (high humidity) and why fog (a very humid condition) often burns off over the course of the morning.
• If the humidity is higher than usual for your area, a storm or rain is probably on its way.

Wind direction:

• A change in wind direction often brings a change in the weather pattern, except if that wind is light.
• The wind direction can also inform you about the type of air that is brought in. If you have the ocean to the north and a desert to the south, wind from the north will bring moist air and wind from the south will bring dry air.

Temperature*:

• Other variables can help predict if the temperature will rise or fall. One needs the current temperature to make a more exact prediction.

Wind speed*:

• Storms are accompanied by higher speed winds.

Precipitation*:

• Precipitation is a variable that indicates what happened before. It is linked with the passage of or absence of a storm, rain, snow, hail, etc., in the past.

* Links in the additional background section provide more information on these variables.

Air pressure is a powerful predictor of the weather. Air is made up of gas molecules such as nitrogen, oxygen, and carbon dioxide. All of these molecules press down on the Earth, and this pressure is called air, or atmospheric pressure. At sea level, the air pressure ranges from 800 to 1050°millibars (23.6 to 31.0 InHg). Because warm air is less dense, it rises which results in lower air pressure near Earth. While it rises, air cools and, in the process, water vapor in the air condenses into liquid. This leads to cloud formation and rain. "Low pressure," therefore, is generally associated with cloudy and rainy weather. On the other hand, high-density cold air results in increased air pressure. As cold air sinks, it dries, causing dry weather conditions in "high pressure" zones.

Additional Background Links

• Talking up a Storm-Students Ask: How Do Meteorologists Predict the Weather, GPB media
• 6 tools our meteorologists use to forecast the weather, National Oceanic and Atmospheric Administration

More information on air pressure and barometers

• What is Air Pressure?, Fun Science for Everyone

Lesson on temperature and making a homemade thermometer

• Make a Thermometer to Study the Temperature, Science Buddies

Lesson on precipitation and making a homemade rain gauge

• Make a Rain Gauge to Study Precipitation, Science Buddies

Lesson on wind speed and making a homemade anemometer

• Make an Anemometer to Measure Wind Speed, Science Buddies

More information on how to use sky coverage to predict the weather

• How to Predict the Weather Using Clouds, Independent News
• What is a cloud?, Eschool Today

Prep Work (20-60 minutes)

• To engage your students, you will share a weather forecast like the one shown in Figure 1. This site provides a good example forecast. Additionally, you can search for your city or find a location nearby. The example site has both an hourly forecast and the forecast for the next couple of days, and it lists temperature, wind speed, precipitation, humidity, and sky coverage. If you prefer a different forecast, choose one that provides a similar amount of information.
• Decide what the weather station will look like for your class. The table below shows a list of variables commonly used to predict the weather, together with the instrument measuring this variable. A third column provides ideas on how students can make these instruments.
  
  

  Weather-related variable	Tool used to measure	Instructions on how to build the instrument
  Sky coverage	Your eyes
  Temperature	Thermometer	Lesson
  Precipitation	Rain gauge	Lesson
  Wind speed	Anemometer	Lesson
  Optional: Wind direction	Windsock, weather vane
  Optional: Humidity	Hygrometer	Lesson
  Optional: Air pressure	Barometer

  Table 1. List of weather-related variables and the instruments that measure them.

  The following questions and remarks can guide your decision:

  • Do you have instruments at hand? Do you have enough instruments for several weather stations?
  • Is there time for the students to build instruments and acquire a deeper understanding about the variable it measures? Can you split the class in groups and let each group build one instrument?
  • Can you use instruments from another teacher, the library, etc.? Is there money to buy instruments?
  • Alternatively, if no instruments can be obtained for one or a few of the essential variables, students can collect real-time data online.
  • More measurements can lead to more discoveries but can also increase the time to make graphs and analyze the data.
• Decide how your class will write down the measurements. Table 2 is an example data collection table for a class using store-bought instruments.
  
  
  Swipe left to see more

  Weather Station Data: [insert location]
  Date/Time	Sky coverage	Temperature [°F]	Humidity [%]	Wind speed [mph]	Precipitation [mm]

  Table 2. Example data collection table.

  The following hints can guide your decision:

  • If there is one weather station: All students take turns reading the instruments and adding data to the table. Suggestion: Have the table on a poster board accessible to all.
  • If there are several weather stations: Each station has its own data collection table and groups of students need access to the table. Suggestion: Have the table on a paper in a plastic folder securely attached to the weather station.
  • The table can also be made in an electronic data collection and graphing tool like Excel or Google Sheets. If you use this option, check that students do not accidentally erase or alter previous entries. Make frequent backups.
  • Making the table(s) in advance for the students is extra work for the teacher; creating them together as a class or in small groups creates an opportunity to teach students what is important in making data collection tables, but consumes class time.

  Find more details on data collection tables in the Set up data collection section of Explore.

• This step can be done any time before you ask students to find weather connections in their data in the Find connections section of Explore. Look at the Weather Connections file. It lists some weather conditions that frequently occur together. These will be referred to as weather connections or simply connections. The connections listed in the file are globally valid. Other weather connections will be typical for your area. Print the Weather Connections file and cut the sheet into cards, and/or use additional paper to create cards with connections students can test using their data. Only choose connections that use the data students collect, e.g. if students do not collect data on humidity, then skip the connection stating, "If the temperature rises, then humidity decreases." Aim to have at least one card per group of 3 to 5 students. If needed, use the same connection several times.

Engage (40 minutes)

Set the stage

Show the class a local weather forecast for the coming days (info on how to select a weather forecast to share can be found in the Teacher Prep section). An example weather forecast is shown in Figure 4. Then start a class discussion.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies

A five-day weather forecast for San Francisco, CA during a week in August. The list has columns that describe the weather conditions, high and low temperatures, chance of precipitation as a percentage, wind direction/speed and humidity as a percentage for each day.

Figure 4. Five-day weather forecast for San Francisco.

How do you think weather forecasters make weather forecasts like this one?

Listen to students' ideas and elicit logical reasoning about the process of forecasting the weather. Do not correct or add. This question will be answered throughout the course of the lesson.

Explore how weather forecasting is done

Create groups of 3 to 5 students. Students will tackle some questions in groups before sharing their ideas with the class.

Imagine our class goes on a camping trip. Why would it be helpful to know the weather forecast beforehand?

The weather forecast helps the class stay prepared and safe. If the forecast predicts it will be hot, we know to take a lot of water, a hat, and sunscreen if we go on a long hike. If the forecast predicts a storm is coming, we can reschedule our hike and secure our tents or anything that might fly loose in a storm.

On our camping trip, we can bring some tools, but we cannot expect to have electricity or cell phone reception, so we will not be able to access the weather forecast via internet, radio, or TV. We need to learn to forecast the weather ourselves! If we had to predict what the weather will be like in a few hours, what would you do to make that prediction?

Let the students briefly work on the question in groups and write down their answer on the worksheet.

Ask a group about how they would predict what the weather will be in a few hours.

If students have difficulties, give an example following the structure provided below. Insert the local weather conditions and use an existing or made-up weather connection.

Example 1:

• State what the weather is like now: I see very dark clouds in the sky.
• Possible weather connection: Dark clouds bring heavy rain.
• Your prediction: It will rain.

Example 2:

• State what the weather is like now: It is a warm morning, and the sky is clear.
• Possible weather connection: When the sky is clear, temperatures rise over the course of the morning.
• Your prediction: It is going to be hot outside around noon.

Re-state some predictions the class made into the following pattern:

• You look at what the weather is now.
• You use a weather connection, or the link between the current weather and the future weather, to predict what the weather will be like.

Conclude the class discussion by stating the pattern used to make weather predictions:

• We look at the current weather.
• We use weather connections or what particular weather conditions frequently occur close together to predict the future.

We need data of the current weather. How would you describe what the weather is currently like? What variables do we use to describe the weather?

Help students find the variable that is connected with their descriptions e.g. hot and cold are indications of the temperature; windy is a measure of wind speed; etc.

Follow up question: What other weather-related data would be useful to make predictions?

If needed, let students look at the weather forecast shown initially to get ideas.

Data on the following variables is useful to predict the weather: Sky coverage (clear sky, partially clouded, ... ) Temperature (how warm or cold the air is) Humidity (how moist the air is, or how much water vapor the air carries) Wind speed (how fast the wind blows) Wind direction (from what direction the wind blows) Air pressure (how much the air presses on the Earth) Precipitation (how much water fell from the sky recently)

Briefly explain what the variables are as they are mentioned. For most variables, students will get a better understanding of it once they start measuring. You might need to explain humidity and air pressure. Two optional short experiments that can help clarify these variables are listed below. These experiments can be done now or later in the lesson.

Optional: For humidity, let students breathe against their hands and feel how humid the air they breathe out is. What they feel is the water that is in our breath in the form of water vapor. If possible, show water vapor that rises from a cup of tea or hot cocoa. A hygrometer is the instrument that measures how much water vapor is in the air.

Optional: For air pressure, take an empty, flimsy plastic water bottle. Close it with the lid and let students try to squeeze the bottle. Open the bottle and let them try again. As a last test, take a new bottle and let a student suck out air from the bottle. Let students express their observations and challenge them to explain what they observed. They will not be able to crush the bottle when it is closed because the air inside the bottle presses against the inner walls of the bottle, keeping them stiff. They will find it easy to crush the bottle when the bottle is open because the air inside can rush out; very little pressure pushes back. In the last test, they will see that the bottle caves in when a student sucks air out. This happens because the reduced amount of air inside the bottle presses less and less against the inner walls. The air outside the bottle still pushes with the same force against the outer walls. This imbalance makes the bottle carve in.

We need data of all the variables mentioned above. How can we collect this data? What do you do if I ask you how the weather is now? How can we collect data in numbers rather than in descriptions?

We can look outside, go outside and feel what the weather is like, or use tools to measure the weather quantitatively (which means expressed in numbers). Below a list of tools used for each variable listed above.

Explore (3 hours, spread out over 2 to 2.5 weeks)

Set up data collection

• Help the students set up their weather station. Ideally, it should at least include a thermometer, an anemometer, and a rain gauge. If possible, add a hygrometer and a barometer, as these measurements are helpful in predicting the weather.
• As a class, go over each instrument. Explain or let a student explain what the instrument measures, how to read the measurement, and in what units this variable is expressed. Table 4 is included as guidance. You might want to give the students an idea of what the usual range of this variable is for your region during this time of the year.

• As a class, agree on a set of words that will describe the sky coverage. An example could be 'Clear', 'Overcast - white', 'Partially clouded, white clouds', 'Partially clouded, dark clouds', 'Overcast - dark'. As cloud coverage is an easy way to predict the weather, it is advised to collect some details on this variable.
• If you did not make a data table in advance, help students create a data table for the weather station. Table 5 shows an example. The units listed in this table are the units used in commercial instruments. Homemade instruments might not be calibrated. Table 4 lists units that can be used for the homemade instruments if they were built according to the instructions taken from the links listed in Table 1.

This table can be written on paper, a poster board, or stored in an electronic data collection tool.

• Do the first data collection together with your students. Fill in the first row as you explain how you would like them to record the data.

Collect data

• Assign each small group a date and time so they know when it is their turn to collect data. Let small groups of students be responsible for at least one particular date and time, possibly more. Make sure they know where to write down their measurements.
• Collect data every couple of hours, maybe each time the students have a break. If possible, allow students who live relatively close to the school to measure at home in the later afternoon, evening, and early morning with comparable instruments. If school instruments can safely be taken home and returned, that is fine too. Even if they can only measure a few variables like temperature and sky coverage, this data can help discover or confirm connections that happen over the course of a day.
• After collecting data several times a day for 4 to 5 days, switch to collecting data once a day at a fixed time for another week. This data will allow students to see longer-term connections. It is fine if weekends are left blank.

Graph the data

• Make graphical representations of the data. Graph paper works well. If the data table was stored electronically, you might also use a graphing software.

  Some tips to consider:

  • Make separate graphs for the hourly data (taken the first week) and for the daily data (taken the second week) for each variable. This makes finding connections easier.
  • Tell the students how you want them to draw the x-axis. Using the same x-axis makes comparing graphs of different variables easier. You will need to give them two templates for the x-axis, one for hourly data and one for daily data.
  • Make one graph of hourly data and one for daily data together as a class.
    • Start by determining the range for this variable. This is the lowest value in the table and the highest value. The y-axis must cover at least that range.
    • Plot the axes. For the hourly data, make a new graph for each day. Figure 5 is an example of one day.
    • Label both axis and, if applicable, include the unit in which the variable was measured.
    • Plot each measured point on the graph.
    • Optional: connect the points with a line.
    • Give the graph a clear title.
  • Assign sets of data to groups of 3 to 5 students to make the associated graphs. Be available for questions while students practice graphing data. Remember that hourly data will generate one graph per variable per day. You can later glue these graphs together to make a longer timeline as shown in Figure 10.
  • Discuss as a class how you can represent the change in sky coverage over time graphically. One way is to convert the descriptions into numbers, for example, a 0 means 'Clear sky' and the number increases with increasing coverage and darkness of the sky. This system was used in Figure 8.

Figures 5-8 are example graphs. Remember that the data collected in your area will look different. These graphs were made with a graphing software; hand-made graphs made by third-grade students are often a little messier, and that is fine. Different styles (bar graph, line graphs, scatter plot, etc.) were used for these graphs to show the different options. It is sufficient that students know one style.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies

An example line graph shows the temperature over time in San Francisco, CA during the day of August 26, 2019. There are 9 data points collected every 2 hours starting at 6 am and ending at 10 pm. The highest temperature recorded is 65 degrees Fahrenheit at 4 pm and the lowest is 56 degrees Fahrenheit at 6 am.

Figure 5. Example graph of temperature data collected on August 26 in San Francisco.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies

An example line graph shows the humidity over time in San Francisco, CA during the day of August 26, 2019. There are 9 data points collected every 2 hours starting at 6 am and ending at 10 pm. The highest humidity recorded is about 98% at 8 am and the lowest is about 74% at 4 pm.

Figure 6. Example graph of humidity measurements taken on August 26 in San Francisco.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies

An example bar graph shows the wind speed over time in San Francisco, CA during the day of August 26, 2019. There are 9 data points collected every 2 hours starting at 6 am and ending at 10 pm. The highest wind speed recorded is 14 mph at 4 pm and the lowest is 5 mph at 8 am.

Figure 7. Example graph of wind speed measurements taken on August 26 in San Francisco.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies

An example line graph shows the sky coverage over time in San Francisco, CA during the day of August 26, 2019. There are 9 data points collected every 2 hours starting at 6 am and ending at 10 pm. From 6-10 am the sky is fully covered (white sky), then clears up to white clouds at 12 pm and clears further to a clear sky from 2-4 pm. At 6 pm the sky coverage becomes white clouds and then increases until fully covered (white clouds) from 8-10 pm.

Figure 8. Example graph of sky coverage observations taken on August 26 in San Francisco.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies

An example line graph shows the temperature over time in San Francisco, CA during period of August 25 to September 3, 2019. There are 10 data points and one temperature recorded for each day. The highest temperature recorded is 70 degrees Fahrenheit on August 27th, 28th, 31st and September 1st. The coldest temperature recorded is 65 degrees Fahrenheit on August 26th.

Figure 9. Graphical representation of temperature measurements at 4 pm in San Francisco from August 25 to September 3.

Image Credit: Sabine De Brabandere, Science Buddies / Science Buddies

Two example bar graphs show the wind speed over time in San Francisco, CA during the days of August 26th and 27th, 2019. There are 9 data points collected every 2 hours starting at 6 am and ending at 10 pm for each graph. The side-by-side graphs show a pattern of lower wind speeds during the morning that increase to their highest during the mid-late afternoon and then decrease again at night.

Figure 10. Connecting multiple days of hourly data graphs allows us to see daily patterns. The light blue line in the middle is where the two graphs are taped together.

Find connections

Have the weather connection cards ready for this step.

• Introduce the term "weather pattern" by describing your local weather over the past couple of days or weeks. A weather pattern is the repetition of the same type of weather on consecutive days. For example, it can be clear and sunny on consecutive days or it can be windy and wet for a number of days. Clear and sunny or windy and wet is the pattern. Unless something happens (like a drop in air pressure or a turn in direction of a strong wind) the pattern tends to stay the same. Students might see weather patterns in their data.
• Show the cards, shuffle them, and let each group of 3 to 5 students take one card. Ask groups of students to check if the connection on their card is visible in the data that they/the class collected. Walk around and help groups where needed.
• Groups that are done can tackle another connection.
• Challenge the groups to find other connections in their data.
• Let each group present their findings. Their short presentation should include:
  1. The connection they needed to check
  2. The data they used to check for the connection
  3. Their findings
  4. How their data supports their findings
• If groups found more connections, allow them to make more presentations; one presentation per connection. Hang each confirmed connection on a poster board or tape them on the board. Students need to be able to consult these to make their weather forecast.

Make a forecast

• Now that the class found some connections, the real test is: Can they make a forecast?
  Depending on the connections found, you might only assign short term forecasts (e.g. in the morning, they can forecast the weather for noon or early afternoon) or also include longer-term forecasts (e.g. what the weather will be like tomorrow).
  Do not forget to give students access to the confirmed weather connections.
• Each morning, a few groups can make a forecast for the afternoon based on their measured data and present it to the class. If time allows, the class can make a TV frame from an old cardboard box, or students can record a short video of their forecast and play the video instead of presenting directly.
  Note that students need access to the weather station to gather information of current weather conditions before they can make a forecast. If this is not possible, you can give them made-up weather data, or each group can use historical or current data that you looked up.
  The forecast should include:
  1. Current weather conditions (or the conditions of the moment they measured to prepare for this weather forecast)
  2. What the weather will be like.
  3. Use vocabulary learned in the lesson.

If time allows, let them inform the class of the reasoning used to come to the prediction.

Reflect (30 minutes)

Did you find it easy to forecast the weather?

What connection surprised you, and why?

Answers will depend on the experiences of the students.

We looked at a weather forecast at the start of the lesson. It is a 5-day forecast, but we only forecast for a few hours or 1 day. How can meteorologists forecast the weather over several days or even weeks? Do you think they use other tools than those that we had?

Meteorologists (the scientists that make weather forecasts) use the same types of instruments that we did, but their instruments are more precise. Meteorologists also have other tools like radar images, weather balloons, satellites, etc. They have way more data because they gather information from several locations while we gathered data from one location only.

We processed the data manually or with simple graphing tools, but meteorologists use supercomputers to process all their data. They first apply physics and math formulas to predict the weather. Then, they use their experience of what happened in the past to predict the future, just like we did.

Assess

You can use this quiz to assess student learning after the activity.

• Online quiz, assignable in any LMS
• Quiz (pdf) and Answer key (pdf)

You can also evaluate students while they are preparing and presenting their weather forecast. This fun exercise can show if students can read the instruments, if they understand how to make a forecast, and if they can use weather-related terminology.

Make Career Connections

Discussing or reading about these careers can help students make important connections between the in-class lesson and STEM job opportunities in the real world.

Meteorologist

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Career Profile

Meteorologists analyze the measurements and motions of the atmosphere so that they can see connections and predict the weather, just like you did in this lesson. They collect more variables, have more tools, and use more math and physics to make their predictions, but the process is the same. Read more

Climate Change Analyst

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Career Profile

The climate of an area is the weather in that area looked at over a larger period of time. Climate change analysts predict how the climate might shift due to a changing environment. Examples of a shift scientists see now is a rise in temperature, or more frequent extreme weather events. They use this information to make suggestions about what individuals and governments can do to prepare for these changes. Read more

Lesson Plan Variations

• Add a lesson on vocabulary words that describe the weather or that can be used in a weather forecast.
• Have the class look up ways in which you can predict the weather by observing nature. Many plants and animals sense a change in weather and alter their behavior accordingly. For example, high humidity makes pine cones close, leaves curl, and hair frizzle. Low flying birds or bees that stay close to their nest can indicate a low air pressure. The chirping of crickets can even be used as a thermometer. Use these observations and the observations of the sky as described in this lesson as indicators of the weather. To make graphing easier, you can make these observations numerical in a similar way to what was suggested for the sky coverage graphed in this lesson.
• If the class goes on an outdoor trip not too far from the area where the class investigated the weather, practice describing and predicting the weather on the trip. If the class goes to an area with a different climate, observe the differences. Inform students that while some weather connections are global, others are local.
• Use the weather station to explore the weather in different seasons.