Mosquito season in Berkshire County, MA: when it starts and ends

Mosquito months in Berkshire County

In a normal year mosquito season in Berkshire County, MA starts around April 30 and ends around October 10, about 23 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 Berkshire County, 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 10.
• 1 West Nile case since 2016 (last 2018): you should use repellent at dusk July, more so if over 60.

Berkshire County against the rest of MA

Berkshire County has the 14th longest season of 14 MA counties, at 163 days against 194 in Plymouth County and 163 in Berkshire County. Its mean temperature is 45.9°F.

• Essex County: April 28 to October 19 (174 days, 14 WNV)
• Worcester County: April 26 to October 16 (172 days, 7 WNV)

West Nile in Berkshire County

From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Berkshire County (2 neuroinvasive) across 2 years. The worst was 2018 with 1; the latest was 2018.

More: how the dates are worked out · when the season starts across the US.