Cold temperatures still hover in some parts of the United States, but spring officially arrives on March 20. It is the day of the vernal equinox, in which the sun is exactly above the equator and day and night are equal in length all over the earth. Yet spring's coming in the natural world happens not at the turn of a calendar page, but through countless changes, such as crocuses blooming.

A sure sign of seasonal change is the journey north as birds, butterflies, and others animals migrate. Your class can report sightings or check out others students' updates of the migrations they see, from hummingbirds to Northern orioles. They can explore how not only birds but other animals — such as humpback whales — migrate.

Spring is the time as well of newborn and growing life. Kids can also travel to a poultry farm online and find out how the farmer raises chicks in the spring.

Professional spring observers keep their own kind of journals as they track plants in bloom weekly at the Missouri Botanical Garden. Your students can see how spring flowers not just in gardens and meadows, but everywhere by looking at the fishhook cactus and other flora in the desert. It's a sure cure for a cold, gray day!