Throughout my teaching years, I told my students to dress in layers, get outside and embrace winter. On this, the fourth day of meteorological winter, it's time to think about December and winter in Minnesota.

This month is considered the time of gentle snows, but the theme of the month is growing cold. If we do have a storm, it's end usually culminates in a hard cold for several days. The intensity of the sunlight is just a quarter of the maximum level we had back in June. A fresh snow cover reflects close to 90 percent of the sun's radiation. No wonder we experience cold days.

Lakes continue to freeze over. Ice on lakes often echoes with resounding moans and cracks as air temperatures drop. Untold millions of animals — including wood frogs, American toads, painted turtles, black bears, woodchucks, red admiral butterflies, wood ticks and various mosquitoes — are hibernating across the region. Deer begin dropping their antlers. Ring-necked pheasants feed in corn stubble fields. Screech owls often roost in wood duck houses. Gray squirrels also use these nesting boxes for shelter.

Bird-feeder birds such as northern cardinals, nuthatches and downy woodpeckers are numerous and active.

December is full of natural marvels. Take time to celebrate the beauty and wonder.

Jim Gilbert's Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.