Mosquito season in Pondera County, MT: when it starts and ends
Mosquito months in Pondera County
In a normal year mosquito season in Pondera County, MT starts around May 10 and ends around October 2, about 21 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Pondera County, and when
- Start tipping out standing water weekly by April 26.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 2.
- 1 West Nile case since 2016 (last 2018): you should use repellent at dusk July, more so if over 60.
Pondera County against the rest of MT
Pondera County has the 21st longest season of 56 MT counties, at 145 days against 163 in Dawson County and 89 in Gallatin County. Its mean temperature is 44°F.
- Musselshell County: May 7 to October 1 (147 days, 0 WNV)
- Petroleum County: May 7 to September 29 (145 days, 0 WNV)
- Garfield County: May 8 to September 29 (144 days, 1 WNV)
- Flathead County: May 8 to September 28 (143 days, 1 WNV)
West Nile in Pondera County
From 1999 to 2025, CDC ArboNET counted 7 human West Nile cases in Pondera County (2 neuroinvasive) across 4 years. The worst was 2007 with 3; the latest was 2018.
See how the dates are worked out, and when mosquitoes go away for the winter.