Mosquito season in Northeastern Connecticut Planning Region, CT: when it starts and ends

Mosquito months in Northeastern Connecticut Planning Region

In a normal year mosquito season in Northeastern Connecticut Planning Region, CT starts around April 25 and ends around October 17, about 25 weeks.

What to do in Northeastern Connecticut Planning Region, and when

Start tipping out standing water weekly by April 11.
Book any yard treatment for late April, ahead of the July peak.
Repellent can go away after October 17.
No West Nile cases since 2016, so bites in Northeastern Connecticut Planning Region are a nuisance; check window screens.

Northeastern Connecticut Planning Region against the rest of CT

Northeastern Connecticut Planning Region has the 8th longest season of 9 CT counties, at 175 days against 200 in Greater Bridgeport Planning Region and 164 in Northwest Hills Planning Region. Its mean temperature is 48.7°F.

Naugatuck Valley Planning Region: April 20 to October 23 (187 days, 0 WNV)
Western Connecticut Planning Region: April 19 to October 22 (186 days, 10 WNV)
Northwest Hills Planning Region: April 30 to October 11 (164 days, 0 WNV)

West Nile in Northeastern Connecticut Planning Region

CDC ArboNET lists no human West Nile cases for Northeastern Connecticut Planning Region from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 3 of those years.

Background: when mosquitoes go away for the winter; how the dates are worked out.