FleaDates › Tick season › New Hampshire
Northeast · NH
When are ticks active in New Hampshire?
Ticks in New Hampshire are typically active late March to late November, heaviest May–Sep — and adult blacklegged ticks can surface on any mild winter day.
Ticks to know in New Hampshire
Blacklegged ticks are the main concern here, thick in the southern counties and steadily working their way up the river valleys, with activity from late March to late November and the worst of it May through September. American dog ticks share the summer months in fields and along dirt roads. A dog that hikes the Whites in October can still come home carrying adult blacklegged ticks, so the end of summer is not the end of tick checks.
Wherever the calendar sits this month, the habit that actually catches ticks is the after-walk check: ears, collar line, armpits, between the toes. Prevention plus checks beats either alone.
Month-by-month tick activity in New Hampshire
| Month | Typical activity | Average temperature |
|---|---|---|
| January | Quiet | 24°F |
| February | Quiet | 26.5°F |
| March | Low | 35°F |
| April | Moderate | 46.8°F |
| May | High | 57.8°F |
| June | Peak | 66.9°F |
| July | Peak | 72.4°F |
| August | Peak | 70.9°F |
| September | Peak | 62.9°F |
| October | Moderate | 50.8°F |
| November | Moderate | 40.1°F |
| December | Quiet | 29.9°F |
Estimates from NOAA U.S. Climate Normals (1991–2020), averaged across 2 weather stations near New Hampshire's larger cities, using the ~40°F activity threshold reported in published tick research. Real years run early or late with the weather.
Fleas peak later. New Hampshire flea season typically runs mid-April to late October — see the New Hampshire flea season page.
Frequently asked questions
When does tick season start in New Hampshire?
Around late March in a typical year, once temperatures clear roughly 40°F — noticeably earlier than flea season. A February thaw can bring ticks out ahead of schedule.
What ticks live in New Hampshire?
The species dog owners most often meet in New Hampshire: blacklegged (deer) tick, American dog tick. Blacklegged ticks are the main concern here, thick in the southern counties and steadily working their way up the river valleys, with activity from late March to late November and the worst of it May through September. American dog ticks share the summer months in fields and along dirt roads. A dog that hikes the Whites in October can still come home carrying adult blacklegged ticks, so the end of summer is not the end of tick checks.
Do I need tick prevention in winter in New Hampshire?
Yes. Ticks overwinter under leaf litter and snow rather than dying off, and mild spells wake them — which is why veterinary organizations recommend year-round parasite prevention. The calendar shows when pressure peaks, not when protection can lapse.
What about fleas in New Hampshire?
Fleas run on a warmer calendar — in New Hampshire that's mid-April to late October. See the New Hampshire flea season page for that month-by-month picture.