Let’s look at the colors shown in this satellite image of the eastern United States. It was taken in April. Green colors show spring green-up, where warm temperatures have promoted plant growth. Brown colors show areas that are waiting for warmer temperatures and spring green-up.

Milkweed and spring flowers need many days of warm weather to grow. Where could the monarchs find the spring vegetation they need? Name the states.

Monarch flight is affected by temperature, too. Monarchs can not fly unless their muscles are 60 F. Which states have “flight-friendly” temperatures for migrating monarchs at this time of year? Find a temperature map and see!

What do you think about the hypothesis that monarchs move northeast at this time of year because of spring vegetation and temperatures?