Mosquito season in Clark County, NV: when it starts and ends
Mosquito months in Clark County
In a normal year mosquito season in Clark County, NV starts around January 20 and ends around December 9, about 46 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Clark County, and when
- Start tipping out standing water weekly by January 6.
- Book any yard treatment for mid January, ahead of the July peak.
- Repellent can go away after December 9.
- 76 West Nile cases since 2016: you should wear EPA-registered repellent at dusk May to October, and check NV spray notices.
Clark County against the rest of NV
Clark County has the 1st longest season of 17 NV counties, at 323 days against 323 in Clark County and 107 in White Pine County. Its mean temperature is 69.6°F.
- Mineral County: April 5 to November 1 (210 days, 0 WNV)
- Esmeralda County: April 12 to October 23 (194 days, 0 WNV)
West Nile in Clark County
From 1999 to 2025, CDC ArboNET counted 169 human West Nile cases in Clark County (118 neuroinvasive) across 17 years. The worst was 2019 with 43; the latest was 2024.
More: how the dates are worked out · reading the West Nile counts.