When the Bay Area air turns crisp and you finally pull out that old sweater from the back of the closet, you might think pests are done for the year. They’re not. They’re just moving inside — right along with you.
Rodents: Mice and Rats
Cold weather sends rodents into homes faster than almost any other pest. They can squeeze through dime-sized holes, crawl up drain pipes, and climb along branches that brush against your roof. Once inside, they chew wires, nest in insulation, and contaminate pantries.
What helps: Seal entry points with steel wool and caulk. Keep food sealed in airtight containers. Trim tree limbs that touch your home. Call a professional if you hear scratching or see droppings — rodents multiply fast.
Ants
In mild Bay Area climates, ants stay active year-round — especially species like Argentine ants and odorous house ants that love moisture and warmth. When it’s cold, they move indoors searching for food or shelter from the rain.
What helps: Wipe up crumbs and spills immediately. Keep counters dry. Check around windows and pipes for gaps. Use professional-grade bait rather than spray treatments.
Spiders
As insects move inside seeking warmth, spiders follow their food source. Most indoor spiders in the Bay Area are harmless, but the western black widow is present and worth monitoring in garages, storage areas, and crawlspaces.
What helps: Reduce clutter in garages and storage areas. Regularly sweep down webs. Seal gaps around utility penetrations and doors.
Cockroaches
German cockroaches thrive in warm kitchen and bathroom environments year-round. Outdoor species like the Turkestan or oriental cockroach may move indoors during rainy, cold weather to seek shelter.
What helps: Fix leaky pipes and faucets. Keep kitchen appliances and behind cabinets clean and dry. Seal gaps around plumbing under sinks.
When to Call ATCO
If you’re seeing signs of any of these pests — droppings, chewing, trails, webs, or live activity — the fall and early winter is the right time to address it before populations establish themselves. ATCO serves the Bay Area, Sonoma County, and Marin County with year-round pest management services. Contact us for an assessment.