Mosquito season in Washoe County, NV: when it starts and ends
Mosquito months in Washoe County
In a normal year mosquito season in Washoe County, NV starts around April 28 and ends around October 13, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Washoe 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 13.
- 31 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check NV spray notices.
Washoe County against the rest of NV
Washoe County has the 9th longest season of 17 NV counties, at 168 days against 323 in Clark County and 107 in White Pine County. Its mean temperature is 50.8°F.
- Storey County: April 26 to October 23 (180 days, 0 WNV)
- Nye County: April 25 to October 11 (169 days, 2 WNV)
- Douglas County: May 11 to October 13 (155 days, 12 WNV)
- Pershing County: May 4 to October 4 (153 days, 0 WNV)
West Nile in Washoe County
From 1999 to 2025, CDC ArboNET counted 61 human West Nile cases in Washoe County (27 neuroinvasive) across 14 years. The worst was 2017 with 25; the latest was 2023.
See how the dates are worked out, and reading the West Nile counts.