Beware: Mosquito season will soon be upon us. Here's what you need to know

The sun is out and the flowers are blooming as Canadians once again emerge into a beautiful spring and summer season. But as people shed their winter layers, our blood-sucking nemeses — mosquitoes — are also emerging into the warmer weather.

The end of May always brings with it the onset of mosquitoes, but their intensity will depend on the rain, according to mosquito experts.

"One thing that is a good predictor of how bad the mosquito season will be is how wet it is, because mosquitoes breed in stagnant water," said Rosalind Murray, entomologist and assistant professor at the University of Toronto.

Murray said that last year, Ontario saw a rough mosquito season due to a relatively mild winter and spring. Female mosquitoes generally overwinter — or hide out in the cold winter months — and then emerge as soon as the weather is warm. The milder weather meant they were out in full force, Murray said.

This year, a chillier early spring could keep mosquitoes low, but in regions with rain and higher temperatures forecast, that could lead to a strong start for the mosquitoes. Environment Canada's seasonal forecast for May to July suggests precipitation to be below normal in some parts of Alberta and B.C. Meanwhile most of the country could have temperatures above normal in the next three months, according to the federal agency.

"If indeed we have above normal temperatures and we have a lot of precipitation and coupled with all the snow we had late winter, the soil is still a little bit saturated," said Alice Sinia, entomologist at Orkin Canada. 

"So we're going to have a lot of soggy soil and we're going to have a lot of stagnant water or pounds of water around."

Beware of standing water

That's a key breeding ground for mosquitoes, especially in cities. And it's part of what makes them such a problem for people.

"One thing that's really difficult about mosquitoes is that they breed in really gross water," Murray said. 

"They don't have gills, so they get their oxygen even when they're in their aquatic life stage from the air. And so because of that, they are able to breed in pretty disgusting, oxygen-deprived water."

But even without excess water, some mosquitoes could still thrive. John Soghigian, assistant professor of parasitology at the University of Calgary, says there around around 80 species of mosquitoes in Canada, and some have even adapted to drought-like conditions.

"The mosquitoes have lived through a lot of the kind of ups and downs of rainy or dry seasons, and they still find ways to be out there and biting us," he said.

Sinia also pointed out that mosquitoes can thrive in various environments, down to small flower pots and other objects that can hold water.

"So that means even within the city, even if you don't have these big ponds and stagnant waters, you can still have mosquito activity."

The experts recommended eliminating sources of stagnant water on people's properties to keep mosquitoes at bay. For those going out, they recommend bug spray, especially for outdoor activities like hiking. Health Canada has a list of approved personal insect repellents. 

Toronto Public Health said that it will begin spraying catch basins and stagnant water sites where mosquito larvae have been identified likely in early June, because that is when the risk of West Nile Virus typically begins.