Guide · preserved from the original PestFactor

Pittsburgh's year-round pest calendar

Pest control in Pittsburgh isn't a summer hobby — it's a twelve-month rotation. Three rivers, old housing, and wooded suburbs mean something is always active. Here's the calendar the local pros work from.

Spring (Mar–May): emergence

Overwintering pests wake up: ants (carpenter ants in damp wood are the structural concern), termite swarmers, and early mosquitoes as standing water warms. This is inspection season — a spring perimeter check catches infestations before they establish.

Summer (Jun–Aug): peak pressure

Mosquitoes near the rivers and floodplains, ticks in the wooded suburbs (Lyme is a real regional risk — treat yards and check pets), wasps and hornets nesting in eaves, and spotted lanternflies, now established across western PA. Cockroach activity peaks in warm, moist basements.

Fall (Sep–Nov): the invasion

The big one. Cooling weather drives mice, rats, and overwintering insects indoors — seal entry points before the first cold snap. Stink bugs cluster on sunny walls. This is the highest-value exclusion work of the year.

Wildlife is year-round: raccoons, squirrels, and bats don't read calendars — attic invasions happen in every season here. If you hear scratching overhead, that's a wildlife removal specialist, not an exterminator with a spray can.

Winter (Dec–Feb): indoor pests

Mice and rats established in fall now breed indoors; German cockroaches thrive in heated buildings. Winter is the time for attic inspection and planning only — bats may be hibernating in the attic itself, and sealing then can trap them inside. Exclusion happens when the roost is confirmed empty, which a professional verifies before anyone picks up a sealant gun; a pro can plan that spring work now.