Mosquito season in Daniels County, MT: when it starts and ends
Mosquito months in Daniels County
In a normal year mosquito season in Daniels County, MT starts around May 19 and ends around September 16, about 17 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Daniels County, and when
- Start tipping out standing water weekly by May 5.
- Book any yard treatment for mid May, ahead of the July peak.
- Repellent can go away after September 16.
- No West Nile cases since 2016, so bites in Daniels County are a nuisance; check window screens.
Daniels County against the rest of MT
Daniels County has the 48th longest season of 56 MT counties, at 120 days against 163 in Dawson County and 89 in Gallatin County. Its mean temperature is 40.3°F.
- Missoula County: May 23 to September 22 (122 days, 0 WNV)
- Deer Lodge County: May 25 to September 23 (121 days, 0 WNV)
- Judith Basin County: May 25 to September 18 (116 days, 0 WNV)
- Silver Bow County: May 27 to September 17 (113 days, 0 WNV)
West Nile in Daniels County
CDC ArboNET lists no human West Nile cases for Daniels County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 2 of those years.
Background: when the season starts across the US; how the dates are worked out.