Mosquito season in Blaine County, NE: when it starts and ends

Mosquito months in Blaine County

In a normal year mosquito season in Blaine County, NE starts around May 1 and ends around October 10, about 23 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Blaine County, and when

• Start tipping out standing water weekly by April 17.
• Book any yard treatment for early May, ahead of the July peak.
• Repellent can go away after October 10.
• 1 West Nile case since 2016 (last 2024): you should use repellent at dusk July to August, more so if over 60.

Blaine County against the rest of NE

Blaine County has the 84th longest season of 93 NE counties, at 162 days against 200 in Richardson County and 127 in Sioux County. Its mean temperature is 49.5°F.

• Arthur County: April 30 to October 12 (165 days, 0 WNV)
• Box Butte County: May 1 to October 10 (163 days, 11 WNV)
• Thomas County: May 1 to October 10 (162 days, 2 WNV)
• Keya Paha County: May 1 to October 9 (161 days, 0 WNV)

West Nile in Blaine County

From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Blaine County (1 neuroinvasive) across 4 years. The worst was 2003 with 2; the latest was 2024.

Background: when mosquitoes go away for the winter; how the dates are worked out.