(NC)—After months of waiting, spring has arrived – so allergy sufferers beware.

It's a little known fact that year-round weather actually has a profound influence on the allergy season for the coming year. Different trees adapt to cope with various environmental stresses, so the pollen season varies from year to year. This makes it difficult to predict how bad pollen counts will be at any given time.

“While a particularly hot summer can trigger a large amount of pollen to be released the next spring, a cold spring can delay the pollen season by several weeks,” says Dr. Ross Chang, President, British Columbia Society of Allergy & Immunology.

Those much dreaded spring showers may seem inconvenient, but allergy sufferers should be grateful. Rain washes pollen out of the air, while wind disperses it, carrying allergens throughout the environment.

Once spring turns to summer, smog adds another environmental problem to the allergy mix. “Smollen” – or the combination of smog and pollen in the air – is becoming a well-recognized term among allergy sufferers across Canada.