Most pests don’t disappear in winter: they shelter in protected places outdoors, survive the cold as eggs, or move into heated buildings where food and warmth are easy to find. Spiders and many insects slow down in leaf litter, woodpiles and wall voids, mice and some cockroaches look for warm spaces indoors, and mosquitoes wait out the cold as dormant adults or eggs. Saela Pest Control is a residential and commercial pest control company that treats each of the pests covered here. Below is where four familiar pests go in winter and what you can do about each; Saela’s guide to the most common winter pests and Montana State University Extension’s guide to fall home invaders cover several more.
Spiders: sheltering outdoors or already inside
Many spiders you notice indoors in winter were already living in the house, while outdoor spiders shelter in leaf piles, woodpiles, rocks and other protected spots. Montana State notes that, like insects, many spiders seek a protected place to spend the winter, and UC IPM’s pest note on spiders explains that they get indoors through cracks and openings or ride in on plants, firewood and boxes. Most spiders are beneficial because they feed on pest insects, so the practical steps are to vacuum regularly, seal foundation cracks and gaps around windows and doors, and keep firewood outside until you use it. If spiders keep turning up after that, see Saela’s spider control service.
Cockroaches: the indoor species never leave
Cockroaches don’t migrate indoors for a winter nap; the ones that matter in winter are the species already living inside and the outdoor species that wander in. UC IPM’s pest note on cockroaches explains that German cockroaches live indoors year-round in warm, humid places near food and water, such as kitchens and bathrooms, while American, oriental and Turkestan cockroaches live outdoors but can temporarily invade. Store food in sealed containers, keep trash in bins with tight lids, fix plumbing leaks and seal cracks around doors and windows. Because treatment depends on the species, identify the cockroach first; for German cockroaches, Saela’s cockroach control uses gel baits, crack-and-crevice applications, monitoring devices and a follow-up visit.
Rodents: active all winter and looking for a way in
Mice and rats don’t hibernate, and UC IPM notes that house mice often move indoors in autumn when nighttime temperatures drop and can breed year-round when food and shelter are steady. Mice can fit through a hole the width of a pencil, so CDC’s guide to sealing out rodents recommends filling small holes with steel wool held in place with caulk or spray foam, and using hardware cloth, metal sheeting or cement for larger gaps. Check where utility lines enter, around vents, along the foundation and under eaves, then look inside under sinks, behind appliances and near the furnace and water heater. Droppings, fresh gnaw marks and tracks show where mice are already active.
Mosquitoes: dormant adults and eggs
Mosquitoes don’t simply die off when it gets cold; depending on the species, they survive winter as dormant adults, as eggs or as slow-growing larvae. The Contra Costa Mosquito and Vector Control District explains that Culex and Anopheles females shelter in places such as culverts and underground storm drains from late October or November until warmer weather, often in late February or early March. Some Aedes species spend part of the year as eggs, and CDC notes that Aedes eggs stick to the inside walls of containers and can survive drying out for up to 8 months. Scrubbing out buckets, planters and birdbaths in fall, not just emptying them, removes eggs that would otherwise hatch in spring.
Saela’s rodent exclusion service includes inspecting for access points, repairing openings and placing traps for rodents still inside. In a February 2024 Google review, Alexander Dove wrote, “They always do a great job keeping pests out of our house.”
Every Saela plan includes a 50+ point property inspection covering entry points, attics and basements, which are the places overwintering pests tend to settle. Saela’s pricing page explains how plans are quoted.
If mice, cockroaches or spiders are already showing up this winter, book a call with Saela to schedule an inspection. Saela’s Orem, Utah headquarters holds an A+ rating and accreditation from the Better Business Bureau.
Who wrote this article?
Devin Hutchings (Marketing Director at Saela Pest Control) wrote this article.
Devin leads Saela’s marketing and growth strategy. He brings more than 15 years of marketing experience across Uber, C.R. England, Lugg, and Neighbor. His background spans customer acquisition, retention, and developing marketing channels for service businesses and consumer marketplaces.
