When is mosquito season?

Mosquito season in southern Ontario – including Toronto and the GTA – typically begins in late April to early May, just as it is now, and continues through the fall as long as the weather stays warm. But it’s not just about dates on a calendar. When mosquitoes come out depends more on temperature and moisture than on specific times of year.

Mosquitoes are extremely active when temperatures are consistently higher than 10°C every day and humidity is high. Thus, they begin breeding in spring with torrential rain and continue through the humid summer months, mainly around puddles, vegetation, and clogged gutters.

The heaviest mosquito activity typically starts in late May and peaks from June to August, when the weather becomes hot and humid. Warm, wet weather accelerates the hatching of mosquito eggs, causing swarms, which are especially noticeable at sunset.

Some mosquitoes, such as those that are vectors of West Nile Virus, hatch slightly later in the season, turning a seasonal nuisance into a potential health risk.

Due to these factors, it's essential to take action early. If you wait until people are being bitten, then you're already reacting to a problem that's on the rise. By initiating trapping and the removal of breeding sites in May, you can control the population before it becomes unmanageable.

Seasonality & Activity Levels
 

Month	Avg. Temp (°C)	Mosquito Activity	Recommended Action
April	8–12	Low	Inspect gutters & remove debris
May	12–18	Moderate	Deploy traps; prune deadwood
June	18–24	High	Add repellent plants; screen porches
July–Aug.	24–28	Peak	Intensify trapping; replace water weekly
Sept.	18–22	Moderate	Continue habitat checks
Oct.	10–16	Low	Final clean-up; store equipment

 

 

How to Help Prepare for Mosquito Season?

When Are Mosquitoes Most Active?

Mosquitoes tend to be most active on warm, calm evenings – generally from 7 p.m. to 11 p.m. in Toronto. If it is not too hot or cold and the sky is dark, your breathing, body heat, and normal odors become more noticeable to them.

To get ready for mosquito season, three major areas need to be focused on: habitat, protection, and control.

Start off by looking around your property for anything that can hold water for longer than a few days. This would be clogged eavestroughs, flowerpots, tarps, or toys. Even small standing water may be the ideal breeding ground for mosquitoes.

Next, be sure to make arrangements for your safety. Apply mosquito repellent during hours where mosquitoes are most active, do not wear dark colors, and screen doors or porches. For extra comfort, mosquito netting over the hammock or outdoor seating area is used by over some individuals.

The final step is the use of traps or natural repellents. Place outdoor traps in secluded, quiet areas. Plant mosquito-repelling herbs like lavender, basil, or citronella. And don't forget the fans – even light breezes will keep mosquitoes away.

A routine and efficient prevention measure will keep you away from most summer infestations. Do not wait until an emergency – maintaining your trees by way of regular trimming is far better than removing them in due course.

 

 

Peak Daily Activity
 

Time of Day	Light Level	Mosquito Biting Risk	Tip
Dawn (5–7 AM)	Low	High	Wear long sleeves
Early Evening (7–9 PM)	Dusk	Very High	Use repellent & fans
Night (10 PM+)	Dark	Moderate	Close windows; turn on lights

 

Habitat vs. Control Measures

Breeding Site	Tree/Yard Feature	Control Measure
Clogged gutters	Eavestroughs	Clear & flush weekly
Puddles in low spots	Poorly draining soil	Aerate soil; re-grade around root zones
Dense undergrowth	Thick shrubs	Prune lower branches; thin dense foliage
Planters & toys	Any container holding water	Empty/turn over containers; drill drainage holes

 

 

Who Can Help Me Prepare for Mosquito Season?

This is a common question in the GTA: what month do mosquitoes come out, and whom should I call when they do?

It's mostly thought by people that pest control companies take care of mosquito management, but it's actually your landscaping or tree care crew that first detects the issue. That's because they're checking your landscape regularly, drainage systems, and plant health.

Tree professionals can identify mosquito-friendly conditions well before mosquitoes become a problem. For example, poorly draining soil makes the perfect breeding ground. Thick shrubs that create cool, moist areas? Mosquito paradise. That's why pre-spring tree maintenance - like pruning deadwood and deep root feeding - can keep mosquitoes away, even if mosquito control isn't your top priority.

Aside from this, arborists can also spot areas of low air movement or where water settles in proximity to tree roots. Addressing these spots makes your house less appealing to mosquitoes.

If you have not yet made your spring plans, contact landscaping or tree care professionals in early May. You will be a step ahead of the rest and have a more comfortable, bug-free outdoor space in June.

 

 

Best Mosquito Control Service in Toronto

We hear it every spring: Are mosquitoes out yet? In May, the simple answer is that they have started to wake up. They will reach their peak in the month of June.

When you need actual assistance, find a local professional who knows about the types of insects and geology of your area. That's where Tree Doctors comes in to help.

Even though we're not an extermination service, we maintain Toronto's outdoor areas daily. That makes us experts at preventing mosquito breeding sites from occurring – and, better yet, preventing the issue from worsening. We root out sources of excess moisture in your yard by pruning selectively, checking the soil, and choosing plant groups that allow fresh air to circulate.

Our services include guidance on how to place mosquito traps, how to protect honeybees, and how plants naturally repel mosquitoes.

We practice green practices, and chemical fogging is a last resort. We seek to bring things into balance, so you can live outdoors in harmony with nature for the trees, birds, and all the rest.

Call us if you're planting, pruning, or getting ready for your patio. We'll keep the mosquitoes from your yard so that you can have the best of your summer.