Mosquito season in Northwest Hills Planning Region, CT: when it starts and ends

Mosquito months in Northwest Hills Planning Region

In a normal year mosquito season in Northwest Hills Planning Region, CT starts around April 30 and ends around October 11, about 23 weeks.

What to do in Northwest Hills Planning Region, and when

Start tipping out standing water weekly by April 16.
Book any yard treatment for late April, ahead of the July peak.
Repellent can go away after October 11.
No West Nile cases since 2016, so bites in Northwest Hills Planning Region are a nuisance; check window screens.

Northwest Hills Planning Region against the rest of CT

Northwest Hills Planning Region has the 9th longest season of 9 CT counties, at 164 days against 200 in Greater Bridgeport Planning Region and 164 in Northwest Hills Planning Region. Its mean temperature is 46.3°F.

Western Connecticut Planning Region: April 19 to October 22 (186 days, 10 WNV)
Northeastern Connecticut Planning Region: April 25 to October 17 (175 days, 0 WNV)

West Nile in Northwest Hills Planning Region

CDC ArboNET lists no human West Nile cases for Northwest Hills Planning Region from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 2 of those years.

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