FleaDates › Tick season › Connecticut
Northeast · CT
When are ticks active in Connecticut?
Ticks in Connecticut are typically active mid-March to early December, heaviest May–Oct — and adult blacklegged ticks can surface on any mild winter day.
Ticks to know in Connecticut
Lyme disease takes its name from a Connecticut town, and the blacklegged ticks that carry it remain the state's defining parasite, questing from mid-March until early December with pressure heaviest May through October. American dog ticks join in across fields and trail edges in late spring and summer, and lone star ticks have been pushing into the coastal towns along the Sound. The adult blacklegged ticks out questing in fall — active on any mild autumn day — are the ones dog owners most often miss.
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 Connecticut
| Month | Typical activity | Average temperature |
|---|---|---|
| January | Quiet | 30°F |
| February | Quiet | 32°F |
| March | Low | 39.3°F |
| April | Moderate | 50°F |
| May | High | 60.3°F |
| June | Peak | 69.7°F |
| July | Peak | 75.5°F |
| August | Peak | 74.1°F |
| September | Peak | 66.7°F |
| October | High | 55.2°F |
| November | Moderate | 44.7°F |
| December | Low | 35.4°F |
Estimates from NOAA U.S. Climate Normals (1991–2020), averaged across 2 weather stations near Connecticut'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. Connecticut flea season typically runs early April to early November — see the Connecticut flea season page.
Frequently asked questions
When does tick season start in Connecticut?
Around mid-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 Connecticut?
The species dog owners most often meet in Connecticut: blacklegged (deer) tick, American dog tick, lone star tick. Lyme disease takes its name from a Connecticut town, and the blacklegged ticks that carry it remain the state's defining parasite, questing from mid-March until early December with pressure heaviest May through October. American dog ticks join in across fields and trail edges in late spring and summer, and lone star ticks have been pushing into the coastal towns along the Sound. The adult blacklegged ticks out questing in fall — active on any mild autumn day — are the ones dog owners most often miss.
Do I need tick prevention in winter in Connecticut?
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 Connecticut?
Fleas run on a warmer calendar — in Connecticut that's early April to early November. See the Connecticut flea season page for that month-by-month picture.