Mosquito season in Gem County, ID: when it starts and ends
Mosquito months in Gem County
In a normal year mosquito season in Gem County, ID starts around April 28 and ends around October 12, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Gem County, and when
- Start tipping out standing water weekly by April 14.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 12.
- 7 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to August, more so if over 60.
Gem County against the rest of ID
Gem County has the 9th longest season of 44 ID counties, at 167 days against 194 in Canyon County and 85 in Fremont County. Its mean temperature is 48.4°F.
- Twin Falls County: April 26 to October 13 (171 days, 10 WNV)
- Power County: April 26 to October 11 (168 days, 0 WNV)
- Bingham County: April 28 to October 9 (164 days, 2 WNV)
- Franklin County: April 30 to October 10 (163 days, 2 WNV)
West Nile in Gem County
From 1999 to 2025, CDC ArboNET counted 49 human West Nile cases in Gem County (11 neuroinvasive) across 13 years. The worst was 2006 with 15; the latest was 2024.
More: how the dates are worked out · reading the West Nile counts.