While preschoolers may have a certain understanding of the changing seasons, due to the changing temperatures, when teaching winter themes you can further explain how and why the seasons change. When outlining a winter theme, take time to discuss the other seasons and how they differ from winter. Using visual demonstrations such as a bright sun for summer, red/orange leaves for fall, snow for winter and blooming flowers for spring the preschooler is able to understand winter is a normal part of the seasonal changes.
After discussing the various seasons, with an emphasis on winter, the children may wonder why the seasons change -- specifically, why winter is so cold. Inform children why the colder months are vital to the survival of plants and animals. For example, teach students that without the colder air, certain insects would make too many babies, thus causing an infestation. Ensure the children understand winter is part of the earth's natural balancing act.
Snow is perhaps the most notable theme when teaching preschoolers about winter. Inform the children how snow is the same as rain, but due to the colder temperatures the rain freezes and becomes white flakes. Use photographs of snow flakes to showcase the changes water undergoes when transforming to snow. This is also a good time to teach the children about temperatures and when a temperature reaches a certain degree, water either freezes or melts.
The winter theme should be taught with the help of activities. Not only will activities physically engage the children, but the visual nature of an activity may help instill the teachings. Make a snowman out of a sock, decorate cut-out snowflakes or create a matching game using different colored winter-themed items such as mittens. Winter activities are available online as well as in teaching resource books focused on preschool.