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

Mosquito months in Capitol Planning Region

In a normal year mosquito season in Capitol Planning Region, CT starts around April 16 and ends around October 25, about 28 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Capitol Planning Region, and when

• Start tipping out standing water weekly by April 2.
• Book any yard treatment for mid April, ahead of the July peak.
• Repellent can go away after October 25.
• 5 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to August, more so if over 60.

Capitol Planning Region against the rest of CT

Capitol Planning Region has the 2nd longest season of 9 CT counties, at 193 days against 200 in Greater Bridgeport Planning Region and 164 in Northwest Hills Planning Region. Its mean temperature is 51.6°F.

• Greater Bridgeport Planning Region: April 16 to November 2 (200 days, 2 WNV)
• Southeastern Connecticut Planning Region: April 18 to October 28 (193 days, 2 WNV)
• South Central Connecticut Planning Region: April 19 to October 29 (192 days, 5 WNV)

West Nile in Capitol Planning Region

From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Capitol Planning Region (3 neuroinvasive) across 2 years. The worst was 2023 with 3; the latest was 2024.

Background: reading the West Nile counts; how the dates are worked out.