Seasonal Pest Alerts for GTA Homeowners

Want to stay ahead of seasonal pest problems? Get a professional inspection before the season changes.

Pest activity in the GTA follows predictable seasonal patterns. Understanding when different pests are most active gives you a window to prevent problems before they start. Here is your month-by-month guide to what to watch for in and around your GTA home.

January to February: Rodent Peak Season

Mice and rats are at their most active inside GTA homes. Cold outdoor temperatures mean they are fully settled in, breeding, and reproducing. This is when you are most likely to hear them in the walls at night.

• Inspect for droppings in the basement, garage, and utility rooms weekly
• Keep the basement dry and well-ventilated
• Store items in sealed plastic bins, not cardboard boxes
• If you hear mice in the walls, call a licensed operator immediately

March: Wildlife Season Begins

Raccoon denning season starts. Females are waking from their winter slow period and looking for warm, sheltered spaces to give birth. Attics are prime real estate.

• Inspect roof vents, soffits, and fascia for damage
• Trim tree branches back from the roof
• If you hear sounds in the attic, call a wildlife operator immediately
• Do not block any entry points you find until a wildlife operator confirms the space is empty

April to May: Raccoon and Squirrel Peak

The busiest months for wildlife calls. Baby season means female animals are protective and more defensive. They also cannot be trapped or relocated while caring for young.

• Do not attempt wildlife removal yourself during baby season
• If wildlife has entered the attic, a licensed operator will need to wait until babies are mobile before completing exclusion
• Seal any new gaps you find in exterior walls

June: Ant Season Starts

As temperatures warm up, carpenter ants and pavement ants become active. Carpenter ants in particular can cause significant structural damage during the spring and summer months.

• Watch for carpenter ant swarmers (winged ants) near windows and light sources
• Store food in sealed containers and clean kitchen surfaces daily
• If you see ants inside your home, do not wait for them to establish a colony

July to August: Wasp and Fly Peak

Peak season for wasps, flies, and outdoor pests. Wasp nests grow most rapidly in late summer. By August, a small nest can become a large one.

• Inspect under eaves, deck railings, and porch ceilings weekly for new wasp nests
• Small nests are easier and cheaper to treat. Act immediately.
• Keep garbage bins sealed and at least 10 feet from doors
• Cover food at outdoor gatherings

September: Mice Season Starts

This is the most important month for pest prevention. Mice start looking for winter shelter as temperatures drop. Any gap larger than 6 mm is a potential entry point.

• Seal every gap in the foundation, walls, and roofline
• Install door sweeps on exterior doors
• Move firewood away from the house
• Schedule an annual perimeter treatment with a licensed operator
• Store bird seed in metal bins

October to November: Mice Prevention Window Closes

If mice have not found a way in by November, the risk of an infestation drops significantly. But the window for prevention is closing.

• Do a final exterior inspection before winter sets in
• Check weather stripping on all exterior doors
• If you have not done your fall pest prevention yet, do it now
• Watch for signs of mice: droppings, gnaw marks, sounds in the walls

December: Winter Watch

Most pest activity moves inside. Focus shifts to early detection of any mice that did find their way in during the fall.

• Set snap traps or bait stations in the basement and garage as a precaution
• Monitor for any signs of mice every week
• Keep storage areas clean and organised so signs of pests are easier to spot

Frequently Asked Questions

What month do mice start coming inside in the GTA?

September. As nighttime temperatures drop below 10 degrees, mice start seeking warm shelter. October is peak entry month.

When is raccoon season in Toronto?

March through May is baby season. Prevention work should be done in fall before denning season begins.

Are pest problems seasonal in the GTA?

Some pests are highly seasonal: wasps peak July through September, mice peak October through March. Others like cockroaches can be year-round problems.

When should I schedule annual pest control?

Two optimal windows: early spring (March or April) and early fall (September or October). These are when pests are most active in seeking new shelter.

Do pests get worse with climate change in Toronto?

Yes. Warmer winters reduce pest mortality, extend breeding seasons, and allow new species to establish populations.

Need a seasonal pest check? Get free quotes from licensed pest control operators in the GTA.