Spring has hit the city, bringing warmer (and rainier) weather, longer days, blooming trees, and, for many New Yorkers, the dreaded sniffles and sneezes of allergies.

City residents who suffer from the maladies may be in for a long season, one leading allergist says.

“It looks like because of the mild winter, it’s going to be a very early allergy season,” the medical director of Allergy and Asthma Care of New York, Dr. Clifford Bassett, said. Dr. Bassett, a clinical instructor at the New York University School of Medicine, said a mild winter tends to “trick the trees” into budding earlier.

Many New Yorkers who may think they have had the flu in the past several weeks actually have allergies, he said. “What we’re seeing is a lot of people coming in with coughing, wheezing, shortness of breath – and they don’t even recognize their symptoms,” Dr. Bassett said.

Tree pollen dominates the early spring, with grass and weed pollen cropping up later in the season and into the summer. The height of the spring season comes around Easter, when both tree and grass pollen are prominent.

Whether people with seasonal allergies experience symptoms depends on the weather, which affects the pollen count. Rain tends to keep the pollen count low, while dry, windy weather increases it, Dr. Bassett said.

The American Academy of Asthma, Allergy, and Immunology tracks pollen counts across the country on its Web site. Yesterday’s tree pollen count was 40 on a scale of 1,500, which qualified as within the moderate range. Because of yesterday’s rain, today’s pollen levels are expected to be low, but they should increase to high levels later this week, Dr. Bassett said.

At Boyd’s Pharmacy on Columbus Avenue on the Upper West Side, the spring season brings a 25% spike in sales for allergy medications, the supervising pharmacist, Robert Annicharico, said. “We have definitely seen an increase” this season, Mr. Annicharico said.

While people can experience allergies as early as February, they often don’t buy medication until late March or early April. The strong sales typically last through June. “They tend to wait until they really suffer,” Mr. Annicharico said.

Waiting is not the answer to allergies, Dr. Bassett said, especially for people who aren’t sure what their symptoms mean. “The key to this is to get tested and to get treated,” he said.

For more than a third of people with seasonal allergies, eating certain foods can exacerbate sensitivity and symptoms, Dr. Bassett said. During the tree pollen period, risky fruits and vegetables include apples, hazelnuts – even in coffee – carrots, celery, cherries, pears, and kiwi. Potatoes, melon, and tomatoes also can be a problem with grass pollen.

“It’s not just what’s in the air, but it’s also what you take into your body,” Dr. Bassett said.

In a list of “survival tips” for the 2006 season, Dr. Bassett advises New Yorkers with allergies to check pollen counts on a daily basis and not to exercise outdoors between 5 a.m. and 10 a.m., when pollen counts are highest. Allergy sufferers should make sure to keep windows closed and air conditioning recirculating to keep out pollens. They should wash at night to remove pollens that collect during the day.

A final recommendation is perhaps the most appealing: Take a vacation by the sea, where pollen counts often are lower.