• Optional: Anemometer (to measure wind speed; if not available, wind speed can be estimated)
• Compass (to measure wind direction)
• Thermometer (if possible, a max/min type)
• Rain gauge
• Daily Weather Observations data sheet

Procedure

1. Discuss the usefulness of long-term weather data with your students. Tell them that weather records dating back over a hundred years are maintained for many locations throughout the world, and discuss why this is useful. They will probably mention that weather records help in predicting the weather. However, biologists can use weather records to help understand patterns in the natural world. This will be how they use the data they collect in this lesson.
2. It is best if students actually collect weather data themselves. This can be done at school, the task assigned to individual students. If students do not collect the weather data, they can get it from sources such as newspapers, TV, or the Internet.
3. Set up a time and location to collect weather data. Wind and cloud cover records should be taken at the same time each day. If you do not have an anemometer, estimate wind speed as strong, breezy, light, or calm. Cloud cover can be clear, partly cloudy, mostly cloudy, or overcast. If possible, get a high and low temperature for each day. Use a rain gauge placed in a location where it will not be disturbed or affected by trees, bushes, or roof overhangs.
4. The amount of time over which you record weather data is up to you. If you live in the southern part of the country, there may be monarchs in your area in March or April, and you could keep track of the weather from this time until the end of the school year. If you live in the north, you may want to start recording weather conditions as soon as migrants are reported in the south. Students could then compare conditions in their location to those where monarchs are being seen.
5. Have students analyze their weather data in some way. They can graph temperature over time, cumulative rainfall, the percentage of days with different amounts of cloud cover, or anything else they can think of. You may want to have each student choose something different to analyze. They should come up with a specific question (e.g. How does the spread between daily high and low temperatures vary during the month of April?), choose the data they need to answer the question, and make a graph that will best show the answer to that question.
6. There are many ways to relate weather conditions to monarchs and their host plant, milkweed. Questions to consider include: