Do warm winters really mean ticks are active all year in New Hampshire now?

Not quite, and the honest answer sits between two extremes. Adult blacklegged ticks have always been active on any day the ground and air stay above freezing without snow cover — a normal winter thaw isn't new. What's changed is that New England has genuinely warmed over the past century, especially in winter minimum temperatures, and that supports somewhat more winter tick activity and a longer overall disease-risk season. But this is a modest, measurable shift, not a claim that ticks are now active every single winter day or that a New Hampshire winter no longer offers any reduction in tick pressure — that stronger version overstates what the data shows.

Is there research showing tick-borne disease seasons are actually getting longer in New England?

Yes — a peer-reviewed New England study found the babesiosis season, meaning the months per year with reported cases, expanded from an average of about 2.2 months before 2000 to about 9.2 months after 2015, and researchers linked part of that expansion to warmer winters. This is a genuinely sourced, specific data point rather than a general climate-change assumption, and it supports taking winter tick activity seriously in New Hampshire rather than assuming risk disappears once summer ends.

Does a warmer winter mean my pet's mosquito and heartworm risk is now year-round too?

No — heartworm transmission through mosquitoes is temperature-gated in a way ticks aren't. Heartworm larvae cannot develop inside a mosquito below about 57°F (14°C), so even in a warmer year, New Hampshire's heartworm-transmission window is lengthened, not eliminated or made year-round by warming alone. That said, veterinary and parasitology organizations recommend year-round heartworm prevention regardless, as a risk-management choice rather than because transmission is literally happening every month — which is a decision your veterinarian can walk through with you.

Should I stop doing yard tick-habitat work in winter since it's cold anyway?

No — this is one place the evidence pushes against a common assumption. Because adult ticks quest on any above-freezing, snow-free day, leaf-litter and brush-edge management genuinely still matters through a New Hampshire winter, not just April through November. That said, winter yard work functions more as a holding action than the primary lever — there's no yard treatment that fully offsets a warm-winter effect, so pairing continued habitat management with regular pet checks and your veterinarian's prevention recommendation is the honest, complete approach rather than yard work alone.

Daniel Brady · NH-Licensed Pesticide Applicator · License #782664

Warm Winters: How Tick and Mosquito Risks Change for Pets

Yard & Vet

Off-season yard habitat management is Anchor's holding-action lane through winter, and whether your pet needs year-round versus seasonal prevention because of a longer risk window is a conversation for your veterinarian.

The honest calibration matters here: a mild winter really does modestly extend tick and disease-risk pressure — but it does not mean New Hampshire has 'no more winter break,' and that overstated version isn't supported by the data.

At a glance

Whose desk: Yard & Vet
The rest lives at: Ticks & fleas FAQ

The honest router

Whose job is this, really?

Pet-parasite questions belong to three genuinely different owners. Here's the desk that actually owns this one — even when the honest answer is 'not us.'

Whose job is this?

Yard & Vet

The yard — our laneYour vet's desk

Anchor's genuine lane

The one yard lever

This is the one thing a pest company actually owns: your yard. Sorted by what genuinely reduces exposure — primary first, theatre last.

SupportingQuick DIY
Keep leaf-litter and edge management in place through winter, not just in-season
Adult blacklegged ticks quest on any day the ground and air stay above freezing, so leaf-litter removal and brush-edge management don't become irrelevant just because it's a mild New Hampshire winter. Maintain the woodland-edge barrier and litter management year-round rather than assuming a hard freeze will do the job for you — because in a mild winter, it often won't.
Note: This is a holding action in winter, not the primary in-season lever — there is no yard treatment that reliably 'cures' a warm-winter effect.

Who owns the rest

This hub owns pet-specific prevention

The general biology, the mosquito Q&A, the pet-product safety — those live in siblings that already earn them. Here's exactly where.

Winter tick checks and removal technique live at /ticks-fleas-faq; heartworm-vector context lives at /mosquito-faq. Whether year-round versus seasonal prevention makes sense for your pet given a longer risk window is a veterinary decision this page doesn't make.

Ticks & fleas FAQ

General tick and flea biology — species, life cycle, disease basics — lives here.

Mosquito FAQ

General mosquito questions — bites, breeding, season, repellents — live here.

Local to New Hampshire

How this calibrates for NH

New Hampshire context

New England has warmed roughly 1.83°C between 1900 and 2010, most of it since the 1980s and most pronounced in winter, with winter minimum temperatures up about 3.2°C over that span. NH Fish & Game confirms the state's growing season is lengthening with fewer frost days, and Concord's 1991–2020 climate-normal frost-free season runs about 146 days. This supports a modest, real lengthening of tick activity, not a dramatic 'ticks never stop' claim that overstates the sourced data.

NH-licensed applicator #782664 (NHDAMF, RSA 430) · NEPMA member · family-owned since 2017.

Follow-up questions

Frequently asked

Sources(4)

[1]
peer-reviewed study (PMC12343110)
Increasing Length of the Babesia Season in New England in the Climate Change Era
[2]
NH Fish & Game
Rising Temperatures and Climate Change — lengthening growing season, fewer frost days
[3]
NOAA/National Weather Service
Concord, NH Seasonal Climate Normals 1991-2020 — frost-free season data
[4]
CAPC (Companion Animal Parasite Council)
Heartworm guidelines — year-round prevention recommendation

Written & reviewed by

Verified

Daniel Brady

NH-Licensed Pesticide Applicator · License #782664 (NHDAMF, RSA 430)

Daniel Brady is the New Hampshire–licensed applicator behind Anchor Pest Services, a family-owned pest control company serving the Manchester area since 2017.

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Warm Winters: How Tick and Mosquito Risks Change for Pets

Whose job is this, really?

The one yard lever

Keep leaf-litter and edge management in place through winter, not just in-season

This hub owns pet-specific prevention

How this calibrates for NH

Frequently asked

Your next step

Tick season by climate: highest-risk months

How to reduce tick habitat in tall grass and leaf litter

How mosquitoes transmit heartworm to dogs

Can ticks survive winter in a yard?

Have a different pest question?