Illinois Nature Guide: December 2026
December brings winter to Illinois — short cold days, the first lasting snow, and the rivers beginning to freeze. Bald eagles gather below the dams, feeders carry the bird life, and the long, dark nights bring the brilliant winter sky and the year's best meteor shower.
What to look for this week
- Bald eagles concentrate at the open water below the Mississippi and Illinois river dams, fishing the churning tailwaters in the season's classic Illinois winter spectacle.
- The Quadrantid meteor shower peaks in a short, sharp burst around January 3 — watch the northeast after midnight from a dark site away from city lights.
- A planning week: order seeds early, and leave any snow banked over perennial beds as the best insulation an Illinois garden gets.
Birds This Month
December birding in Illinois centers on the rivers and the feeders. As the lakes and rivers freeze in the north, bald eagles concentrate at the open water below the lock-and-dam structures on the Mississippi and Illinois rivers — the Quad Cities, Starved Rock, and Pere Marquette stretches draw growing numbers. The last waterfowl linger on open water before the deep freeze, and big flocks of Canada and snow geese winter in the central and southern grain fields.
This is the season of the Christmas Bird Count, when volunteers across the state tally the winter birds. Feeders are busy with northern cardinals, black-capped chickadees, white-breasted nuthatches, dark-eyed juncos, American tree sparrows, and downy and hairy woodpeckers. In irruption years, pine siskins and common redpolls drop in. On the Chicago lakefront, open Lake Michigan water holds gulls, goldeneye, and the occasional snowy owl on the harbor walls and beaches.
What's Blooming
Nothing blooms outdoors in an Illinois December — the prairies and woodlands are frozen and often snow-covered, and the next blooms are three months away. The winter landscape offers color in other forms: the deep-red stems of red-osier dogwood glowing along wet ditches, the persistent fruit of winterberry holly and highbush cranberry hanging bright against the snow, and the bleached, rattling seed heads of coneflower, rattlesnake master, and compass plant standing among the bronze prairie grasses at Midewin and Nachusa. These structural remnants feed wintering finches and sparrows and shelter dormant insects. Indoors, December is the height of amaryllis, paperwhite, poinsettia, and Christmas-cactus season, bringing living color to the windowsill, and the quiet start of the catalog-dreaming weeks when gardeners begin planning the beds they cannot yet touch.
Garden This Month
December gardening in Illinois moves indoors. The beds are frozen and dormant statewide, so this is a month of planning and protecting: leaf through seed catalogs, sketch next year's garden, and inventory and order seeds. Check that mulch and winter protection are doing their job over perennial crowns, strawberries, and fall-planted bulbs, and press back any plants heaved up by early freeze-thaw cycles.
Outdoors, leave snow where it falls over the beds — it's the best insulation the garden gets, holding soil temperature steady through the cold. Gently knock heavy, wet snow off evergreens, arborvitae, and shrubs to prevent splayed and broken branches, but leave dry, fluffy snow in place. On a mild, dry day you can prune dormant fruit trees and oaks. Indoors, tend houseplants and forced bulbs, and clean, sharpen, and store the tools you put away in fall.
Zone 5b (Chicago metro & northern Illinois): the garden is fully dormant under freeze and snow — leave snow banked over perennial beds as insulation, knock heavy wet snow off evergreens to prevent breakage, and turn to seed catalogs and tool maintenance.
Zone 6a (central Illinois): nothing to plant — check that mulch and any winter protection are in place over marginal perennials and fall plantings, and prune dormant fruit trees on a mild, dry day.
Zone 7a (far southern Illinois / 'Little Egypt'): the mildest corner may still hold a few frost-hardy greens under cover; otherwise it is planning, dormant pruning, and protecting tender plantings against the occasional sharp freeze.
What's at the Farmers Market
December markets in Illinois are indoor winter markets and the holiday harvest. The storage crops carry the season: potatoes, onions, garlic, carrots, beets, parsnips, turnips, cabbage, winter squash, and sweet potatoes, all keeping well from the fall, alongside cold-stored Illinois apples and fresh cider. Frost-sweetened kale, collards, and Brussels sprouts may still come from the field or hoop houses.
The holidays bring seasonal goods to the stands: cranberries, sweet potatoes and squash for the table, fresh Collinsville-area horseradish at its sharp midwinter best, evergreen wreaths and cut Christmas trees, and honey, maple syrup, jarred preserves, and eggs. Choose squash with hard rinds and dry stems and store them cool and dry; keep root crops in a cool, dark, humid spot; and store apples cold. The indoor winter markets and a few hardy farm stands keep the local harvest available through the cold.
Night Sky This Month
December's long nights — the longest of the year around the winter solstice on the 21st — and the cold, clear, dry air make for superb stargazing. The brilliant winter sky is back in full glory: Orion climbs the southeastern evening sky with the Pleiades, orange Aldebaran in Taurus, bright Capella, and the twins of Gemini, all part of the great Winter Hexagon wheeling up after dark.
The marquee event is the Geminid meteor shower, peaking around December 14 — often the best, most reliable shower of the entire year, throwing dozens of bright, slow, often colorful meteors an hour from a dark site, and active right from evening (no need to wait for midnight). For the Geminids and the winter sky, the dark skies of the Shawnee National Forest in far southern Illinois far outshine the Chicago-washed north — just dress for the cold.
The printable Illinois night-sky guide lists this year's exact Geminid peak date, moon phase, and planet positions for your location.
Butterflies & Pollinators
There are no butterflies on the wing in an Illinois December — the cold and snow have shut the active season down completely. The summer's butterflies are scattered across the frozen landscape in their hidden, dormant winter forms. The state's monarchs are clustered by the millions in the oyamel fir forests of central Mexico, two thousand miles south. The species that overwinter in Illinois are tucked away here at home: mourning cloaks, eastern commas, and question marks survive the deep cold as adults wedged behind loose bark, in woodpiles, and in unheated outbuildings, kept alive by the natural antifreeze in their bodies, while others wait out the winter as eggs, chrysalises, or dormant caterpillars in the leaf litter and prairie thatch. December is the season to plan next year's butterfly garden — native milkweed for monarchs and a long succession of prairie nectar plants will pay off when warmth finally returns in spring.
Trees This Month
Illinois's trees are fully dormant in December, and the bare woods reveal their winter architecture. The great white and bur oaks spread their broad crowns over the savanna groves and woodlots, many young oaks and the ironwood still clutching tan, papery marcescent leaves that rattle in the wind. The mottled white trunks of the sycamores shine along the frozen rivers, and the shaggy bark of shagbark hickory stands out against the snow.
In the far southern swamps, the bald cypress stand bare and gray over the iced-over Cache River, their knobby 'knees' poking from the frozen sloughs — the only deciduous conifer of southern Illinois, fully leafless now until spring. Where they were planted, eastern white pine, eastern redcedar, and spruces hold the only green in the gray-and-white winter landscape, their boughs catching and shedding the snow as the year closes.
Go deeper with the Illinois guides
The complete Illinois birding, native-plant, wildflower, and night-sky guides — or the whole year in one bundle.
Same month elsewhere: December in Indiana · December in Iowa · December in Kansas