Calgary & Area Pest Activity Report
This page is a running reference on pest pressure across Calgary, Airdrie, Cochrane, Chestermere, Crossfield and Okotoks. It is compiled and reviewed each season by the licensed technicians at The Pest Control Guy, based on the patterns we see in service calls throughout the year. It is meant as a practical guide for homeowners, property managers and reporters — not a scientific survey.
For media and community groups: you are welcome to quote this report with attribution to The Pest Control Guy and a link to this page. For local pest commentary, seasonal data or an interview, call (403) 829-7788 or email Bookings@thepestcontrolguy.ca.
Last reviewed: Summer 2026.
Why pest activity in Calgary and area is its own story
Two things make pest pressure in the Calgary region different from most of Canada. The first is the chinook cycle: repeated freeze-thaw swings through fall and winter push mice, voles and wildlife toward the warmth of homes again and again, rather than once. The second is how fast the region is building. New developments in Airdrie, north Calgary, Cochrane and Chestermere put fresh foundations next to open field and farmland, which is ideal habitat for voles, pocket gophers and field mice moving into landscaped yards.
The result is a longer active season than many homeowners expect, and rodent and wildlife problems that continue well into winter.
Spring: March to May
- Ants become active as soil warms. Pavement ants, field ants and carpenter ants begin foraging indoors, often along baseboards, window frames and kitchen counters.
- Mice that overwintered indoors are most detectable now; snowmelt also exposes exterior runways and entry points that should be sealed before summer.
- Wasp queens emerge and scout nest sites under decks, in sheds, and inside soffits and wall cavities. A nest removed in May is a fraction of the size and risk of the same nest in August.
- Voles leave surface runways and dead grass trails across lawns once snow clears, especially on acreages and yards backing onto green space.
- Pocket gophers resume pushing crescent-shaped soil mounds through lawns and gardens.
Summer: June to August
- Wasps and hornets reach peak colony size and defensiveness from late July into August. Nests appear under decks, in sheds, under roof overhangs, in trees and inside wall voids. Yards with outdoor dining, fruit trees or open garbage see the most activity.
- Mosquitoes rise and fall with rainfall. Standing water in eavestroughs, bird baths, low spots, tarps and unused containers drives local populations more than anything else.
- Ant colonies expand and satellite nests form; carpenter ant activity indoors warrants inspection for moisture and structural nesting.
- Spiders become more visible as their insect food supply grows. Almost all spiders in Alberta are harmless; a sudden increase usually signals another pest nearby.
- Pocket gophers and voles cause the most visible lawn and garden damage of the year through mid-summer.
Fall: September to November
- Rodents moving indoors is the single biggest pest driver of the season. Mice and, less often, rats enter through gaps around utility lines, vents, weeping tile, garage doors and foundation cracks as nighttime temperatures drop.
- Cluster flies and boxelder bugs gather on warm south- and west-facing walls and work their way inside through gaps.
- Spiders move indoors to overwinter, showing up in basements, garages and window wells.
- Wasp nests hit maximum size in early fall before the colony dies off with hard frost; the nest does not reactivate, but scavenging wasps stay aggressive around food.
Winter: December to February
- Mice and rats remain active indoors all winter, nesting in wall voids, attics, storage and appliances. Chinooks briefly reactivate outdoor movement and bring new waves toward heated buildings.
- Wildlife — squirrels, skunks and occasionally raccoons — den in attics, under decks and in sheds. Skunks under a deck in winter become a spring litter problem if not addressed.
- Stored-product pests such as pantry moths and beetles are noticed more as households spend time indoors.
Regional notes
- Airdrie and acreage properties: voles and pocket gophers are consistently heavier here than in established inner-city Calgary, driven by proximity to field and pasture.
- New developments: the first two or three years after a subdivision is built typically bring elevated field-mouse and vole pressure as displaced populations move into new landscaping.
- Established Calgary neighbourhoods: mature trees and older housing stock shift the mix toward carpenter ants, wasps in soffits, squirrels and attic wildlife.
Pests we track year-round
- Mice and rodents
- Ants, including carpenter ants
- Wasps and hornets
- Spiders
- Voles and pocket gophers
- Bed bugs
- Wildlife — squirrels, skunks, raccoons
Seasonal deep dives
- Summer 2026 pest outlook for Calgary and Airdrie
- Summer wasp activity in Calgary and Airdrie
- Summer vole damage in Calgary and area
- Why mosquito activity spikes after rainfall in Calgary
How this report is put together
The observations above are qualitative. They come from the pattern of inspections and treatments our licensed technicians carry out across Calgary and the surrounding communities through the year, compared season over season. They are a guide to what to expect and when to act, not a measured population count. For background on pesticide safety and integrated pest management, see the Government of Canada pest management guide.
Dealing with a pest problem now
The Pest Control Guy provides residential and commercial pest control across Calgary, Airdrie, Cochrane, Chestermere, Crossfield and Okotoks, with licensed technicians, prevention-first treatment and free estimates.