Fall Invaders: Pests That Try to Move In When the Weather Cools Down

As the temperatures drop and leaves start to fall, pests begin preparing for winter — and that often means trying to move into your home.

While summer is known for mosquitoes, ants, and wasps, fall brings its own wave of invaders. These pests are looking for warmth, shelter, and a steady food source, which makes your cozy home the perfect place to spend the colder months.

At Hot Bugz, we know which pests are most active this time of year, where they hide, and how to stop them before they become a full-blown infestation. Let’s take a look at the most common fall pests — and how to keep them out.


1. Rodents (Mice & Rats)

Why they invade: As soon as the weather turns chilly, rodents begin looking for shelter. They can squeeze through gaps as small as a dime (mice) or a quarter (rats) and take up residence in walls, attics, basements, and garages.

Warning signs:

  • Scratching or rustling sounds in walls or ceilings
  • Droppings along baseboards or in cupboards
  • Gnaw marks on food containers or wiring

How to stop them:

  • Seal holes around pipes, vents, and the foundation
  • Store food (including pet food) in sealed containers
  • Keep firewood and outdoor clutter away from the home

2. Spiders

Why they invade: Fall is mating season for many spider species, and they’re more visible as they seek out mates and warm hiding spots. While most are harmless, their presence can be unsettling — and some, like the brown recluse or black widow, are potentially dangerous.

Warning signs:

  • Frequent web sightings in corners, ceilings, or garages
  • Spiders seen indoors near baseboards or window sills
  • Egg sacs in storage boxes or closets

How to stop them:

  • Vacuum corners and behind furniture regularly
  • Keep clutter to a minimum in attics and basements
  • Reduce other insect activity (spiders follow their food)

3. Stink Bugs

Why they invade: These shield-shaped bugs love to bask in the sun on exterior walls, then sneak inside through cracks as temperatures fall. Once inside, they often hide in attics, behind walls, or in window frames.

Warning signs:

  • Live or dead stink bugs on window sills
  • A musty, unpleasant odor when disturbed or crushed
  • Activity near light sources or sunny windows

How to stop them:

  • Seal gaps around windows, doors, and siding
  • Repair or replace damaged screens
  • Use a vacuum to remove them (and empty it outside immediately)

4. Boxelder Bugs

Why they invade: Like stink bugs, boxelder bugs gather in large numbers on sunny sides of homes in the fall. They squeeze into cracks to overwinter and emerge inside when temperatures rise — sometimes during winter warm spells.

Warning signs:

  • Clusters of bugs on exterior walls or windows
  • Red-and-black insects appearing indoors, especially on warm days

How to stop them:

  • Caulk around windows and doors
  • Remove boxelder trees near your home (if possible)
  • Install weather stripping to prevent entry

5. Cluster Flies

Why they invade: These large, slow-moving flies enter homes in fall to overwinter in wall voids and attics. They don’t breed indoors but can be a major nuisance as they reappear in large numbers during warm winter days.

Warning signs:

  • Groups of flies buzzing around upper windows or attic spaces
  • Dead flies near window sills or ceiling corners

How to stop them:

  • Seal cracks and crevices around siding, vents, and trim
  • Install fine mesh screens on attic vents
  • Vacuum up visible flies instead of spraying (which often isn’t effective)

6. Cockroaches

Why they invade: Cockroaches don’t like the cold and will seek out moist, warm hiding places like kitchens, laundry rooms, and basements. Fall is also a time when cockroach activity increases indoors due to less outdoor food availability.

Warning signs:

  • Droppings that resemble ground pepper
  • Egg casings or shed skins
  • A strong, oily or musty odor

How to stop them:

  • Fix plumbing leaks and remove standing water
  • Clean food residue from under appliances and cabinets
  • Take out trash regularly and store it in sealed bins

Fall Pest-Proofing Tips

Here are some simple steps to make your home less inviting to pests this season:

  • Inspect and seal cracks around doors, windows, siding, and utility lines
  • Check weather stripping and door sweeps and replace if worn
  • Clean out gutters and remove leaf buildup near the foundation
  • Declutter garages and basements, which are common entry points and hiding places
  • Schedule a fall pest inspection to catch issues early

When to Call Hot Bugz

If you start noticing pest activity inside your home this fall, don’t wait for it to get worse. Many pests hide out all winter and reproduce quickly, leading to major infestations by spring.

At Hot Bugz, we offer seasonal pest control services designed to protect your home from fall invaders. Our treatments are safe, targeted, and customized to your specific home and pest risks.