An early taste of spring for much of the eastern United States is unwelcome news for those who struggle with seasonal allergies, as pollen counts are increasing earlier and impacts may be felt for a longer period of time this season.

The springlike warmth could alter the timing of the peak of allergy season, triggering symptoms for allergy sufferers sooner than normal.

According to AccuWeather Senior Meteorologist Alan Reppert, the warm air that arrived in late February provided early growing opportunities for plants, which is causing the pollen season to be about 10-20 days ahead of normal in some areas.

In parts of the mid-Atlantic and Ohio Valley that typically have snow on the ground in late February and early March, allergies are already beginning to increase. Thanks to only short bursts of cold air, Reppert expects this trend to continue into the northern Plains and Northeast even with a much earlier start to the pollen season. 

“Much of the Southeast through the East Coast is looking to have increased levels of pollen this year due to the mild end of winter and also the early start to the growing season in many areas,” Reppert said.

Trees have begun to pollinate in several cities across the South and Northeast.

According to the American Academy of Allergy, Asthma and Immunology's National Allergy Bureau, a high concentration of tree pollen has already been reported in Greenville and Charleston, South Carolina; Savannah, Georgia; and Miami and Tampa, Florida.

Elsewhere, York, Pennsylvania, is reporting a high concentration, while a moderate concentration of tree pollen has been observed in Washington, D.C.

Tree pollen peaks in the spring and, along with grass pollen in the summer and weed pollen in the fall, is one of the main types of allergens, according to Dr. Martha Hartz, chair of pediatric allergy and immunology at the Mayo Clinic Children’s Center in Rochester, Minnesota.

“Tree pollen does trigger eye symptoms and sometimes that’s what’s most bothersome to people is their eye symptoms,” Hartz said.

Experts state that allergens tend to flourish on hot and breezy days, while damp and rainy weather tends to clear the pollen from the air.

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Reppert said early warmth could make for a very long pollen year for those with allergies, especially due to an early tree and grass pollen season. 

This April 22, 2013, photo shows Maple trees which release a lot of wind-borne pollen while mold is produced by leaves littering the ground, in Langley, Wash. (AP Photo/Dean Fosdick)

The return of colder air might help mitigate conditions, but it likely won't be enough to slow the spread of pollen fully.

“If the cold air comes in after trees start to pollinate, it can help to slow things for a time, but unless it gets cold enough to freeze the plants and trees, the trees should start right back up from where they started and increase pollen production again,” Reppert said.

Through the second week of March, there could be opportunities for a freeze to develop down into northern South Carolina with normal low temperatures in the upper 30s and lower 40s at night, according to AccuWeather Lead Long-Range Forecaster Paul Pastelok.

"The risk of a freeze will continue through late April and early May from the mid-Atlantic into the Northeast," Pastelok said.

For those who suffer from allergies, it’s best to limit time outdoors on high pollen days, especially during the early mornings and early evenings. Keeping windows closed at night when possible is also recommended.

“The best way to avoid the pollen is to stay indoors and in air conditioning as much as possible," Reppert said.