As temperatures drop in Pittsburgh, you might notice more spiders appearing inside your home. It’s easy to assume they’re coming in from the cold to escape winter weather, but the truth about spiders and winter might surprise you.
Here’s what’s really happening when you spot spiders indoors during the colder months.
The Short Answer: They’re Already Inside
Contrary to popular belief, the spiders you see in your home during fall and winter aren’t coming inside to get warm. They’ve been living in your house all along.
Most common house spiders spend their entire lives indoors. Species like cellar spiders, cobweb spiders, and house spiders are specifically adapted to indoor living. They wouldn’t survive outside even during warm weather because they’ve evolved to thrive in the stable temperature and humidity of your home.
So Why Do You See More Spiders in Fall?
Mating Season
Fall is mating season for many spider species. Male spiders, which normally stay hidden, become more active as they search for mates. This increased activity makes them more visible. You’re not seeing more spiders, you’re seeing spiders that were already there becoming more active and bold.
They’re Getting Bigger
Spiders that hatched in spring have spent all summer and early fall growing. By autumn, they’ve reached their full adult size, making them much more noticeable when you do spot them.
You’re Spending More Time Indoors
As weather cools, people spend more time inside with windows closed and lights on. You’re simply more likely to cross paths with the spiders that share your living space.
What About Outdoor Spiders?
Some outdoor spider species do seek shelter when temperatures drop, but they’re looking for protected outdoor spaces, not the inside of your home. You’ll find them in:
- Woodpiles
- Under deck boards
- In sheds and garages
- Behind shutters and siding
- In leaf litter and mulch
These spiders go dormant or die off when winter arrives. The ones that do accidentally wander inside typically don’t survive long because indoor conditions don’t meet their needs.
Common House Spiders in Pittsburgh
Cellar Spiders (Daddy Long Legs)
These delicate spiders with extremely long legs build messy, irregular webs in corners, basements, and crawl spaces. They’re completely harmless and actually help control other pest populations.
Cobweb Spiders
Also called house spiders, these are the ones building those three-dimensional, tangled webs in corners and along ceilings. The common house spider is brownish and about the size of a nickel.
Wolf Spiders
These larger, hairy spiders don’t build webs. They hunt actively on the ground, which is why you might spot one running across your basement floor. Despite their intimidating appearance, they’re not aggressive toward humans.
Jumping Spiders
Small, compact spiders with large front eyes that can actually jump short distances. These curious spiders are often found on walls and windowsills hunting for prey.
Are House Spiders Dangerous?
The vast majority of spiders found in Pittsburgh homes are completely harmless. They can’t bite through human skin, or if they can, their venom has no significant effect on people.
Pennsylvania does have two medically significant spider species, but they’re rare:
Black Widows are uncommon in western Pennsylvania and prefer outdoor locations like woodpiles and stone walls. Bites are extremely rare.
Brown Recluse spiders are not native to Pennsylvania, despite occasional reports. Confirmed brown recluse populations do not exist in our area.
The spiders in your home are far more afraid of you than you are of them, and they play a beneficial role by eating other insects.
Why You Have Spiders (And What They’re Eating)
Spiders don’t randomly appear in homes. They’re there because you have prey insects for them to eat. If you have spiders, you have an insect problem, even if you haven’t noticed it.
Common spider prey in homes includes:
- Flies and gnats
- Moths
- Mosquitoes
- Ants
- Other small insects
A house with lots of spiders usually indicates an abundance of other pests. The spiders are actually helping control those populations.
How to Reduce Spider Activity in Your Home
Reduce Their Food Source
The most effective long-term spider control is addressing the insects they feed on. Fix screens, seal cracks around windows and doors, keep outdoor lights off when possible (they attract insects), and address any moisture issues that attract bugs.
Reduce Clutter
Spiders love undisturbed areas. Storage boxes, piles of papers, unused furniture, and cluttered basements provide perfect hiding spots. Regular cleaning and decluttering removes spider habitat.
Seal Entry Points
While most house spiders are born indoors, sealing cracks and gaps prevents outdoor spiders from accidentally wandering in. Check around:
- Window and door frames
- Where utilities enter the house
- Foundation cracks
- Gaps in siding
- Attic vents and crawl space openings
Regular Cleaning
Vacuum regularly, especially in corners, along baseboards, and in less-used areas. Remove webs as you find them. Spiders that lose their webs repeatedly will often relocate to better spots (ideally outside or in areas you use less).
Reduce Outdoor Habitat Near Your Home
Keep firewood stacked away from the house, trim vegetation back from the foundation, and eliminate debris piles. This reduces outdoor spider populations near entry points.
When Spider Problems Indicate Bigger Issues
Occasional spider sightings are normal in any home. However, if you’re seeing large numbers of spiders regularly, or if certain areas of your home have heavy webbing, it might indicate:
- A significant insect problem providing abundant food
- Moisture issues creating favorable conditions
- Entry points allowing outdoor pests inside
- Structural issues like gaps in foundations or walls
A sudden increase in spider activity can also signal seasonal pest pressures, like stink bugs or box elder bugs entering your home in fall, which then attract spiders looking for food.
Should You Call a Pest Control Professional?
Most homeowners can manage occasional spiders with regular cleaning and basic exclusion techniques. However, professional help makes sense when:
- You’re seeing spiders constantly despite your efforts
- You have specific concerns about spider species identification
- You want to address the underlying insect population attracting spiders
- You have areas of your home (crawl spaces, attics) that are difficult to access and treat yourself
- You’re dealing with heavy webbing in multiple areas
Professional pest control can address both spiders and their prey insects, providing more comprehensive and longer-lasting results than DIY methods alone.
The Bottom Line on Spiders and Winter
The spiders you see in your home during winter aren’t invading from outside. They’re year-round residents that become more visible during fall mating season. While it’s unsettling to spot them, most house spiders are harmless and actually beneficial.
If spider activity in your home bothers you, or if you suspect an underlying pest problem, focus on reducing their food sources, eliminating hiding spots, and sealing entry points.
Stewart Termite and Pest Control helps Pittsburgh homeowners manage spider problems and the pest issues that attract them. We can assess your situation, identify what’s bringing spiders into your living spaces, and develop a plan to reduce their activity.
Contact us today to discuss your spider concerns and learn about our residential pest control services.