If there's snow outside, take children out to run around and blow off some steam. Since getting everyone dressed in snow gear takes a long time, make the most out of the trip. Fill spray bottles with water and food coloring and let children spray "paint" on the snow. Ask children to lie down and make snow angels, then use their gloved fingers to draw faces or designs onto the impressions. Take some clean snow inside and add some chocolate sauce and sprinkles to make sundaes.
When the weather is getting bleak, prevent children from getting down or grumpy by making your room into paradise. Ask children to choose a warm and happy theme for the room such as the beach or the jungle. Enlist children to come up with ideas for decorations they can create to transform the room. Bring in bright construction paper so students can make cheerful looking crafts. Once you've decorated the room together, crank up the heat for the afternoon and have a party.
Talk about the way different animals deal with winter. Bring in books about hibernation and bird migration. Hang maps on the wall so children can track the path that birds fly during the winter. Take the class outside so they can look for tracks in the snow other than their own. They can follow these tracks up to the boundaries of the school yard and guess what animals made them. Hang bird feeders outside a classroom window so children can see what birds are still in the area during winter.
Remind children that spring is coming, and teach them about planting and caring for plants. Have each child plant his own seeds. Start by having each child poke holes in the bottom of a foam cup, then fill the cup halfway up with soil. Give each child two or three seeds to grow tomatoes, sunflowers or another type of flower. Children can water their plants each day and keep them in front of the window. When the plants are too big for the cups, children can transplant them to containers made from cut-off milk jugs. When spring finally arrives, send the plants home, for children to plant in their yards.