When Are Pests Active?
Month-by-month activity calendars for New Hampshire pests — when they emerge, where they go in winter, what time of night they move, and when to act.
20 pests are active in August.
Pick a month to re-rank every guide by what's a problem then. The strip on each card shows that pest's whole New Hampshire year at a glance — warmer cells mean more activity.
All 20 Pest Timing Guides
Ranked for August · filter by behavior group or browse all guides
Overwintering Invaders
(6)Where Do Moths Go in the Winter? NH Moth Timing Guide
The moth in your NH house all winter is a pantry or clothes moth that breeds indoors year-round — not the outdoor 'winter moth.' Here's how to tell them apart.
Peaks: Jul
Where Do Flies Go in the Winter? NH Cluster Fly Timing
The sluggish flies at NH windows on warm winter days are cluster flies that entered your walls last fall. They don't breed or bite indoors — see the timing.
Peaks: Sep · Oct
When Are Spiders Most Active in the House? NH Spider Guide
Spiders peak indoors in Sept–Oct because mature males are roaming to mate — not fleeing the cold. NH has almost no dangerous spiders. Here's the honest timing.
Peaks: Sep · Oct
When Are Asian Lady Beetles Active? NH Ladybug Timing
Asian lady beetles swarm sunny NH walls on warm October days, then overwinter in wall voids. They don't breed or damage homes — see the month-by-month timing.
Peaks: Oct
Box Elder Bugs in the House in Winter — NH Timing Guide
Boxelder, stink, and conifer seed bugs in your NH house in winter entered last fall to overwinter in the walls. They don't breed or bite — see the timing.
Peaks: Oct
When Do Crickets Come Inside? NH Cricket Timing Guide
Crickets move into NH homes in late summer and fall as nights cool — camel crickets to damp basements, house crickets to warmth. See the month-by-month timing.
Peaks: Jul · Sep · Oct
Nocturnal Rodents
(2)When Are Rats Most Active? NH Rat Timing Guide
Rats are nocturnal and most active 30–60 minutes after dusk and before dawn, year-round in New Hampshire. See the hourly and monthly activity guide and when to act.
Peaks: Oct · Nov
Where Do Mice Go in the Winter? NH Mouse Timing Guide
Mice don't leave for winter — they move into NH homes each fall and stay active and breeding indoors all season. See the monthly activity guide and when to act.
Peaks: Oct · Nov
Overwintering Wildlife
(5)When Are Raccoons Active? Winter, Night & NH Timing
Raccoons don't truly hibernate — they enter winter torpor and den in NH attics and chimneys, foraging at night. See the activity guide and when to act.
Peaks: Feb · Apr · Jun
Where Do Squirrels Go in the Winter? NH Timing Guide
Squirrels don't hibernate — they stay active all winter in NH, caching nuts and denning in dreys and attics. See the monthly activity guide and when to act.
Peaks: Jan · Feb · Jun · Oct · Dec
When Do Birds Nest? NH Timing & Legal Guide
Pest birds nest roughly March–August and roost in NH vents and eaves all winter. See the monthly activity guide and which birds are legal to remove.
Peaks: Apr · May
When Do Bats Leave the Attic? NH Legal Timing Guide
In NH you may not exclude bats mid-May–mid-August (maternity season) — the legal window is mid-August through October. See the monthly guide.
Peaks: Jun · Jul
Where Do Opossums Live in the Winter? NH Timing Guide
Opossums don't hibernate — at NH's northern range edge they forage all winter and shelter in sheds, crawlspaces, and attics to escape frostbite.
Peaks: Jun · Jul
Seasonal Biters & Stingers
(4)Where Do Wasps Go in the Winter? NH Wasp Timing Guide
Wasp colonies build all summer, peak aggressive in Aug–Sep, then die at the first NH frost — only mated queens survive winter. See the month guide.
Peaks: Aug · Sep
When Is Flea Season? Do Fleas Die in Winter? (NH Guide)
Flea season in NH peaks in late summer and early fall, but fleas don't reliably die in winter — heated homes keep them breeding all year long.
Peaks: Aug · Sep
When Is Mosquito Season in NH? Timing & Risk Guide
Mosquito season in NH runs April through October, with EEE/West Nile risk peaking August until the first hard frost (~Oct 19). See the month-by-month guide.
Peaks: Jul · Aug · Sep
When Are Ticks Most Active in NH? Tick & Lyme Timing
Ticks are active in NH any day above 40°F — nearly year-round — but Lyme risk peaks from tiny nymphs May–July. See the month-by-month tick guide.
Peaks: May · Jun · Jul · Oct
Year-Round & Spring
(3)When Do Ants Come Out? NH Ant Season Timing Guide
Ants come out in New Hampshire once temperatures pass ~50°F — early-to-mid April — and stay active through November. See the month-by-month NH activity guide.
Peaks: Jun · Jul · Aug
Are Cockroaches Active at Night? NH Roach Timing Guide
Cockroaches are nocturnal and active year-round inside heated NH homes, so a roach seen in daylight usually signals a heavy infestation. See when to act.
Peaks: Jan · Feb · Mar · Jun · Jul · Aug · Dec
Do Mites Die in the Winter? NH Mite Activity Guide
It depends on the mite: NH clover mites overwinter as eggs, biting chiggers die below 42°F, and indoor dust mites persist all winter. See the full guide.
Peaks: Apr · Jul · Aug · Oct
Not Sure What You're Dealing With?
Whatever the season, Anchor Pest Services offers same-day service throughout Southern New Hampshire.