Mosquito season in Cheshire County, NH: when it starts and ends
Mosquito months in Cheshire County
In a normal year mosquito season in Cheshire County, NH starts around May 2 and ends around October 10, about 23 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Cheshire County, and when
- Start tipping out standing water weekly by April 18.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 10.
- 1 West Nile case since 2016 (last 2024): you should use repellent at dusk July, more so if over 60.
Cheshire County against the rest of NH
Cheshire County has the 5th longest season of 10 NH counties, at 161 days against 170 in Strafford County and 141 in Coos County. Its mean temperature is 45.8°F.
- Belknap County: April 30 to October 13 (166 days, 0 WNV)
- Hillsborough County: April 30 to October 11 (164 days, 0 WNV)
- Merrimack County: May 3 to October 9 (159 days, 1 WNV)
- Sullivan County: May 5 to October 7 (156 days, 0 WNV)
West Nile in Cheshire County
From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Cheshire County (2 neuroinvasive) across 2 years. The worst was 2024 with 1; the latest was 2024.
Background: when the season starts across the US; how the dates are worked out.