Mosquito season in Bristol County, MA: when it starts and ends
Mosquito months in Bristol County
In a normal year mosquito season in Bristol County, MA starts around April 23 and ends around October 24, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Bristol County, and when
- Start tipping out standing water weekly by April 9.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 24.
- 8 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to August, more so if over 60.
Bristol County against the rest of MA
Bristol County has the 5th longest season of 14 MA counties, at 184 days against 194 in Plymouth County and 163 in Berkshire County. Its mean temperature is 50.5°F.
- Norfolk County: April 15 to October 23 (191 days, 6 WNV)
- Nantucket County: May 1 to November 2 (185 days, 0 WNV)
- Barnstable County: April 28 to October 29 (184 days, 7 WNV)
- Hampden County: April 21 to October 19 (181 days, 7 WNV)
West Nile in Bristol County
From 1999 to 2025, CDC ArboNET counted 14 human West Nile cases in Bristol County (9 neuroinvasive) across 11 years. The worst was 2018 with 2; the latest was 2024.
See how the dates are worked out, and reading the West Nile counts.