The San Gabriel Valley Pest Calendar: What Shows Up, and When

Pest pressure in the San Gabriel Valley follows a predictable yearly rhythm. Knowing what's coming lets you get ahead of it instead of reacting — here's the year, season by season.

Spring (March–May): swarm season

Warm afternoons after rain send out termite swarmers — piles of identical wings on sills are the giveaway (here's how to read the signs). Argentine ants wake up hungry and head indoors, and spider egg sacs start hatching around the eaves.

Summer (June–August): the ant surge

Heat drives ant colonies indoors chasing water, spiders work the porch lights, and dry brush sends ticks hunting for hosts. This is peak season for maintenance plans — and the time most kitchen ant trails appear.

Fall (September–November): the great indoors

Cooling nights drive crickets into garages and rodents into attics and walls (often roof rats from fruit trees). The fall seal-up — sealing the gaps before animals move in — is the single highest-value pest visit of the year, especially for foothill-edge homes.

Winter (December–February): nesting season

Rats and mice settle into warm attics, and roaches hug warm plumbing. The quiet months are also the smart time to book termite work — and to think about what next spring's swarm season will bring (see the cost guide on why a plan beats one-offs).