Why Rats Move Indoors in Fall and Winter

Rats move indoors in fall and winter because cooler nights make warm attics and garages more attractive, and winter rain floods ground burrows. In Arcadia, ripening citrus in October and November also draws roof rats close to rooftops right when they're looking for shelter.

That's why fall is the busiest time of year for rat calls in Arcadia, and why most homeowners first hear scratching in the ceiling between October and December. Below we explain what changes each fall, how winter adds to it, and how to seal your home before rats settle in.

Why do rats come inside in fall?

Rats come inside in fall in Arcadia because they need warm, dry shelter as overnight temperatures drop, and homes offer it close to their food. Attics hold heat from the day, and garages block wind and rain.

Seasonal rodent migration is the shift of rats and mice from outdoor nests to buildings as weather cools. Rats don't hibernate. They stay active all winter and need more calories to stay warm, so they look for shelter close to reliable food.

What changes in Arcadia each fall

Several things change in Arcadia each fall that push rats toward homes at the same time.

• Cooler nights: San Gabriel Valley nights often drop into the 50s by November, and attics stay warmer than the outdoors.
• Ripening citrus: oranges and other citrus ripen through fall and winter, giving roof rats food right next to rooftops. UC IPM notes roof rats favor citrus and avocados.
• Drying brush: near the foothills, dry brush means less food and cover, so rodents move toward irrigated yards and homes.
• Young rats spreading out: rats born in spring and summer leave their nests and look for their own territory.

On the north side, homes under heavy oak canopy feel this first. Rodent Control in Santa Anita Oaks calls jump every October as roof rats move from the trees into attics.

How winter rain adds to the problem

Winter rain in Arcadia floods Norway rat burrows along foundations, fences and drains, pushing those rats into garages, crawl spaces and wall voids. Storms can also damage vents and open new gaps.

Norway rats live mainly in burrows 2 to 4 inches wide. When heavy rain fills them, rats look for the nearest dry space, which is often your crawl space or garage. Raised-foundation homes with old vent screens are especially at risk.

Wind and rain can also tear loose vent screens, push in fascia boards and loosen roof flashing, creating entry points that weren't there in summer.

Signs rats have moved in for the season

The signs that rats moved into your Arcadia home for fall and winter usually show up within a few weeks of the first cool nights.

1. Scratching or running in the ceiling at night
2. Droppings in the attic, garage or kitchen
3. Hollowed citrus on your trees
4. Chewed pet food or bird seed bags in the garage
5. Noise under the floor after a rainstorm
6. A check engine light on a car parked in the garage

If you notice any of these in October or November, rats have likely already settled in. Acting now keeps them from breeding through winter.

How to get ahead of fall rats

The best way to get ahead of fall rats in Arcadia is to seal your home in September or early October, before nights cool. If they're already in, trap first and seal right after.

1. Inspect the roof. Look for gaps at roof returns, torn gable vents and loose fascia.
2. Trim trees. Cut limbs back 3 feet from the roof.
3. Check foundation vents. Replace damaged screens with 1/4 inch hardware cloth.
4. Seal the garage. Replace worn door seals and close slab gaps.
5. Manage fruit. Pick citrus as it ripens and clear fallen fruit.
6. Store food. Move pet food and seed into sealed bins.

Our Rodent Exclusion and Proofing in Arcadia covers every one of these points in a single plan. If rats are already in, Rat Control in Arcadia traps them first so you don't seal them inside.

Common mistakes

These are the fall mistakes that lead to bigger rat problems by spring in Arcadia.

• Waiting to see if it goes away. Rats that settle in during fall stay all winter and breed in spring.
• Sealing with rats inside. They chew new holes or die in walls.
• Leaving fruit on the tree. It feeds rats all season.
• Ignoring the garage. Fall garage activity often leads to car wiring damage.
• Using poison. Poisoned rats die in walls, and winter heating can spread the smell.

When to call a professional

Call a professional in fall as soon as you hear rats or find droppings. The sooner rats are trapped and the house is sealed, the smaller the job.

Rodent Control Arcadia handles fall rat jobs across the city. Near the foothills, Rodent Control in Arcadia Highlands often means sealing garages against deer mice and wood rats that move down from the brush as it dries.

Frequently Asked Questions

These are the seasonal questions Arcadia homeowners ask most.

Get help with Rodent Control in Arcadia

Hearing rats now that nights are cooler? Call us for a same-day inspection before they settle in for winter.