Yes, there is pollen in the winter. While counts drop dramatically compared to spring and fall, several tree species release pollen as early as December, and in some regions, winter pollen levels can spike high enough to cause serious allergy symptoms. Where you live matters enormously: a winter in Minnesota looks very different from a winter in Central Texas when it comes to airborne pollen.
Which Plants Pollinate in Winter
A surprisingly long list of trees and grasses produce pollen during the coldest months. Alder, juniper (often called “mountain cedar” in Texas), walnut, tamarisk, bald cypress, and several palm species all release pollen in December or January. Hazel is another early bloomer whose pollen season can begin in late winter, with the exact start date depending on how quickly temperatures climb above freezing.
The most infamous winter pollinator is Ashe juniper, the tree responsible for “cedar fever” across Central Texas. These trees blanket the Hill Country west of Interstate 35, and when conditions are right, they release clouds of pollen so thick they’re visible to the naked eye. Hourly pollen concentrations above 40,000 grains per cubic meter have been recorded in Austin and Junction, Texas. During the 2009-2010 season, Junction recorded over 70,000 grains per cubic meter in a single hour. For context, most spring pollen counts that trigger allergy alerts measure in the hundreds or low thousands.
Eastern red cedars, found farther east in Texas and across the southeastern U.S., pollinate on a similar December-through-January schedule.
What Triggers Winter Pollen Release
Winter-pollinating trees need a period of cold exposure before they can flower, but they don’t need it to stay cold. Once temperatures rise above freezing for several consecutive days, pollen release begins. For hazel, the critical trigger is the arrival of what researchers call “thermal early spring,” when average temperatures consistently stay above 0°C (32°F). If the mean temperature in the 10 days before the expected start doesn’t reach about 4.5°C (40°F), the season can be delayed by 30 to 35 days.
This is why winter pollen is so geographically uneven. In mild climates like Central Texas, the Gulf Coast, and parts of the Pacific Northwest, temperatures regularly cross these thresholds in December and January. In colder northern regions, those same species may not begin pollinating until March.
Winter Pollen Seasons Are Starting Earlier
If your winter allergies feel worse than they used to, there’s a measurable reason. The freeze-free growing season has lengthened in 87% of 198 U.S. cities analyzed since 1970, by an average of 20 days. A 2021 study found that human-caused warming was the primary driver of North American pollen seasons lengthening by 20 days on average between 1990 and 2018. In Lithuania, researchers found alder pollen seasons have shifted earlier by 13 to 34 days over the past two decades, depending on location. The pattern is consistent across the Northern Hemisphere: trees that used to wait until late winter or early spring are now starting weeks sooner.
Winter Allergies vs. a Cold
Because winter pollen overlaps with cold and flu season, many people assume their sneezing and congestion are caused by a virus. A few differences can help you tell them apart.
The strongest signal is itchy, watery eyes. Allergies commonly cause them; colds and flu almost never do. Fever is another clear divider: allergies never cause a fever, while the flu usually does (often 100 to 102°F). Body aches point toward a virus, not pollen. And duration is telling: a cold rarely lasts beyond two weeks, but allergy symptoms persist as long as you’re exposed to the trigger. If your “cold” has been going for three weeks with no fever and your eyes won’t stop itching, pollen is the more likely culprit.
Indoor Allergens Add to Winter Misery
Pollen isn’t the only reason your allergies may flare in winter. Spending more time indoors with windows sealed and the heat running concentrates exposure to dust mites, mold, pet dander, and cockroach residue. Hot, humid houses are breeding grounds for dust mites and mold. Keeping indoor temperature between 68°F and 72°F and relative humidity below 50% helps limit both. Wood-burning fireplaces and stoves can also worsen respiratory allergies by adding smoke and particulates to indoor air.
For many winter allergy sufferers, the real problem is a combination of outdoor pollen and indoor triggers stacking on top of each other.
Reducing Your Exposure
The same strategies that work during spring pollen season apply in winter, with a few adjustments. Stay indoors on dry, windy days, when pollen travels farthest. The best time to go outside is after rain, which washes pollen out of the air. Avoid outdoor activity in the early morning, when pollen counts tend to peak.
When you come inside, remove your outer clothing and shower to rinse pollen off your skin and hair. Don’t hang laundry outside to dry. Keep doors and windows closed when counts are high, and check local pollen forecasts, which many cities report year-round, not just in spring.
For indoor air quality, a portable HEPA filter in the bedroom makes a noticeable difference. If you have forced-air heating, use high-efficiency filters and replace them on schedule. Vacuuming with a HEPA-equipped vacuum catches pollen and dust mite particles that settle into carpet and upholstery. Encasing mattresses and pillows in dust-mite-proof covers addresses another layer of winter allergen exposure. If you start allergy medications before symptoms ramp up, rather than after, they tend to work more effectively at controlling the inflammatory response once pollen counts rise.