San Diego may not experience harsh winters, but the drop in temperature is enough to push many winter pests into homes in search of warmth, food, and shelter. These intruders—known as overwintering pests—can quickly become a nuisance if left unchecked. Understanding which pests are most active and how to deter them will help you keep your home protected throughout the colder months.
Below are the top winter invaders in our region and the most effective prevention strategies recommended by professional pest control San Diego experts.
1. Rodents
Rats and mice are the most common winter pests in San Diego. As temperatures cool, they squeeze into attics, garages, wall voids, and even car engines. Once inside, they contaminate food, chew wiring, and create fire hazards.
Prevention Tips:
- Seal entry points around doors, roofs, vents, and foundations
- Store food in airtight containers
- Keep outdoor vegetation trimmed back from structures
- Remove clutter where rodents can nest
Rodents are among the most destructive overwintering pests, so early detection is key.
2. Spiders
Species like black widows and hunting spiders are more likely to seek shelter indoors during winter. They hide in garages, sheds, and storage areas where they can find insects to feed on.
Prevention Tips:
- Reduce indoor and outdoor clutter
- Seal cracks around doors, windows, and baseboards
- Move stored items off the floor and into sealed containers
- Remove webs promptly to discourage return activity
While many spiders are harmless, venomous species thrive in the winter months.
3. Cockroaches
Roaches remain active all year in coastal climates. During winter, they gravitate toward humid, warm spaces like kitchens, bathrooms, and laundry rooms. German and American cockroaches are especially common.
Prevention Tips:
- Fix moisture issues and plumbing leaks
- Wipe down surfaces to remove food debris
- Clean under appliances and inside cabinets
- Avoid leaving pet food out overnight
Cockroaches are resilient overwintering pests, so sanitation is the first line of defense.
4. Silverfish
These moisture-loving insects show up in bathrooms, closets, attics, and storage areas where paper, fabric, and humidity are plentiful. Winter conditions often drive them indoors, where they feed on books, clothing, and dry goods.
Prevention Tips:
- Improve ventilation and airflow
- Use dehumidifiers in damp rooms
- Store clothing and paper items in sealed containers
- Repair leaks and remove wet materials promptly
Consistent moisture management helps keep silverfish populations under control.
5. Ants
During cold spells, Argentine ants and other species invade kitchens and pantries searching for food and warmth. Even in mild winters, their colonies move closer to structures and exploit tiny entry points.
Prevention Tips:
- Seal gaps around windows, doors, and foundations
- Keep food sealed and surfaces clean
- Remove outdoor debris that shelters nesting ants
- Trim plants away from your home’s exterior
Ants are one of the most persistent winter pests in San Diego.
How AgPest Protects Your Home
AgPest provides comprehensive winter protection designed specifically for Southern California’s pest pressures. Our seasonal pest control services target the most common overwintering pests and help prevent new infestations throughout the colder months.
We offer:
• Winter inspections to detect early activity
• Rodent-proofing for long-term exclusion
• Spider and roach treatments using targeted applications
• Moisture control recommendations to reduce pest-friendly environments
• Customized pest control San Diego plans built for year-round protection
