Mosquito season in Sioux County, NE: when it starts and ends
Mosquito months in Sioux County
In a normal year mosquito season in Sioux County, NE starts around May 17 and ends around September 21, about 18 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Sioux County, and when
- Start tipping out standing water weekly by May 3.
- Book any yard treatment for mid May, ahead of the July peak.
- Repellent can go away after September 21.
- 2 West Nile cases since 2016 (last 2023): you should use repellent at dusk July to July, more so if over 60.
Sioux County against the rest of NE
Sioux County has the 93rd longest season of 93 NE counties, at 127 days against 200 in Richardson County and 127 in Sioux County. Its mean temperature is 46.6°F.
- Sheridan County: May 5 to October 4 (152 days, 5 WNV)
- Banner County: May 12 to September 29 (140 days, 1 WNV)
West Nile in Sioux County
From 1999 to 2025, CDC ArboNET counted 4 human West Nile cases in Sioux County (2 neuroinvasive) across 3 years. The worst was 2023 with 2; the latest was 2023.
See how the dates are worked out, and when the season starts across the US.