Technical reference
Pest activity index
Twelve months of activity for all 41 tracked pests — who is peaking now, who is still dormant, and what to do before each season starts. Ratings run 0 (dormant) to 3 (peak).
Reading · September 2026
21 pests at peak pressure
39 of 41 tracked pests are active or peaking in September. Activity tracks seasonal conditions in most of the US — check your own region and weather before you treat.
- 39
- active now
- 21
- peaking
- 28
- peak in June
- 3
- peak in January
At peak in September
[ 01 ] Full index
Every pest, twelve months
Sorted by pressure in September. Bar height is seasonal activity, never an infestation count. Ratings are general for US homes — see pests by state for how your region shifts the window.
| Pest | Family | Status | Guides | |
|---|---|---|---|---|
| Bed Bugs | Household Insects | Peak in September | Peak | 9 |
| Cockroaches | Household Insects | Peak in September | Peak | 3 |
| Mites | Household Insects | Peak in September | Peak | 1 |
| Pantry Pests | Household Insects | Peak in September | Peak | — |
| Squirrels | Rodents & Shrews | Peak in September | Peak | 3 |
| Stray Cats | Wildlife | Peak in September | Peak | 1 |
| Gophers | Lawn & Garden Pests | Peak in September | Peak | 1 |
| Possums | Wildlife | Peak in September | Peak | 1 |
| Raccoons | Wildlife | Peak in September | Peak | 3 |
| Beavers | Wildlife | Peak in September | Peak | 1 |
| Moles | Lawn & Garden Pests | Peak in September | Peak | 2 |
| Muskrats | Wildlife | Peak in September | Peak | 1 |
| Skunks | Wildlife | Peak in September | Peak | 2 |
| Chipmunks | Rodents & Shrews | Peak in September | Peak | 1 |
| Lizards | Wildlife | Peak in September | Peak | 1 |
| Fleas | Household Insects | Peak in September | Peak | 2 |
| Flies | Household Insects | Peak in September | Peak | 4 |
| Millipedes | Spiders & Crawlers | Peak in September | Peak | 1 |
| Snakes | Wildlife | Peak in September | Peak | 2 |
| Spiders | Spiders & Crawlers | Peak in September | Peak | 2 |
| Wasps & Yellow Jackets | Bees & Wasps | Peak in September | Peak | 3 |
| Birds | Wildlife | Active in September | Active | 1 |
| Rabbits | Lawn & Garden Pests | Active in September | Active | 1 |
| Shrews | Rodents & Shrews | Active in September | Active | 1 |
| Silverfish | Household Insects | Active in September | Active | 2 |
| Voles | Rodents & Shrews | Active in September | Active | 1 |
| Coyotes | Wildlife | Active in September | Active | 1 |
| Ticks | Spiders & Crawlers | Active in September | Active | 2 |
| Armadillos | Lawn & Garden Pests | Active in September | Active | 1 |
| Centipedes | Spiders & Crawlers | Active in September | Active | 1 |
| Rats | Rodents & Shrews | Active in September | Active | 3 |
| Scorpions | Spiders & Crawlers | Active in September | Active | 1 |
| Groundhogs | Lawn & Garden Pests | Active in September | Active | 1 |
| Mice | Rodents & Shrews | Active in September | Active | 4 |
| Moths | Household Insects | Active in September | Active | 1 |
| Termites | Household Insects | Active in September | Active | 6 |
| Ants | Household Insects | Active in September | Active | 6 |
| Bats | Wildlife | Active in September | Active | 2 |
| Mosquitoes | Household Insects | Active in September | Active | — |
| Carpet Beetles | Household Insects | Low in September | Low | 2 |
| Bees | Bees & Wasps | Low in September | Low | 1 |
Peak Active Low Dormant Current month
[ 02 ] Month by month
Who peaks, and when
The pests rated peak in each month. Use it to get ahead of a season instead of reacting to it.
[ 03 ] Seasonal calendar
Seasonal threat calendar
What moves, what to do before it does, where to look.
Fall is the current window
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Spring
Warmth wakes colonies and swarms. Catch problems early, while numbers are small.
Threat watch
- TermitesSwarmers appear on warm days after rain
- AntsScouts find kitchens as colonies grow
- BeesCarpenter bees start drilling fascia boards
- TicksNymphs quest in leaf litter and tall grass
Checklist
- Clear gutters and fix downspouts
- Pull mulch 6 to 12 inches back from the foundation
- Repair window and door screens
- Knock down starter wasp nests under eaves
Inspect
- Window sills (discarded wings)
- Foundation walls (mud tubes)
- Kitchen counters and sinks
- Eaves, fascia and deck rails
Summer
Peak season for insects outdoors, and for stinging insects defending big nests.
Threat watch
- Wasps & Yellow JacketsYellow jacket nests reach full size
- FleasWarm, humid weather speeds the life cycle
- FliesFruit and drain flies breed in days
- CockroachesOutdoor roaches move inside in heat waves
Checklist
- Keep lids on trash and recycling
- Empty standing water weekly
- Keep pets on flea and tick preventives
- Run a dehumidifier in the basement
Inspect
- Ground holes with wasp traffic
- Drains and fruit bowls
- Pet bedding and rugs
- Under sinks and behind appliances
Fallnow
Cooler nights push rodents and overwintering insects to look for a way inside.
Threat watch
- MiceSeeking winter shelter in walls and garages
- RatsMoving closer to buildings as food drops
- SpidersMales wander indoors looking for mates
- SquirrelsNesting in attics before winter
Checklist
- Seal gaps around pipes, vents and utility lines
- Install door sweeps
- Store firewood 20 feet from the house
- Trim branches that touch the roof
Inspect
- Attic and roof vents
- Garage door seals
- Utility entry points
- Pantry and bird seed storage
Winter
Pests already inside stay active in the warmth. Winter is the time to find and fix entry points.
Threat watch
- MiceMost active indoors in the coldest months
- Bed BugsHoliday travel spreads infestations
- RaccoonsDenning in attics and chimneys
- VolesChewing bark under snow cover
Checklist
- Check the attic for droppings and nests
- Inspect luggage after trips
- Keep storage off basement floors
- Wrap young tree trunks with guards
Inspect
- Attic insulation and rafters
- Behind the stove and fridge
- Basement corners
- Chimney cap and flue
[ 04 ] Year at a glance
Seasonal pest activity guide
The four seasons, the pests that drive them, and the move that stops them.
| Season | Months | Most active pests | Key prevention steps |
|---|---|---|---|
| Spring | Mar · Apr · May | Termites Ants Bees Ticks | Clear gutters and fix downspouts · Pull mulch 6 to 12 inches back from the foundation · Repair window and door screens |
| Summer | Jun · Jul · Aug | Wasps & Yellow Jackets Fleas Flies Cockroaches | Keep lids on trash and recycling · Empty standing water weekly · Keep pets on flea and tick preventives |
| Fallnow | Sep · Oct · Nov | Mice Rats Spiders Squirrels | Seal gaps around pipes, vents and utility lines · Install door sweeps · Store firewood 20 feet from the house |
| Winter | Dec · Jan · Feb | Mice Bed Bugs Raccoons Voles | Check the attic for droppings and nests · Inspect luggage after trips · Keep storage off basement floors |
[ 05 ] Method
How to read this index
The 0–3 scale
- 3 · Peak
- Typical conditions for this pest: warm enough, wet enough, food available. Most infestations start here.
- 2 · Active
- Present and looking for indoor entry. Worth sealing gaps before it becomes a problem.
- 1 · Low
- Occasional, weather-dependent. Usually a sign of a bigger problem indoors.
- 0 · Dormant
- Rare or absent outdoors. Any sighting is worth investigating rather than treating.
What this is not
- Activity is a planning aid, not a diagnosis. Confirm the pest before you buy or apply anything.
- Ratings are general for US homes. Your region, microclimate and season shift the timing — see the regional notes in each pest guide.
- Do not treat preemptively. Sealing entry points, storing food sealed and cutting moisture beat a spray you did not need.
- Termites, bed bugs and wildlife in the attic need a professional, whatever the calendar says.
[ 06 ] Pro
Know what's active, then decide if you need a pro
Two weeks of correct DIY with the right bait, trap and sealed entry point is the honest limit. Past that, a pro finds what you cannot see — and you should ask what's included, which product and why, and get the guarantee in writing.