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

Mosquito months in Box Butte County

In a normal year mosquito season in Box Butte 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 Box Butte 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.
• 11 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check NE spray notices.

Box Butte County against the rest of NE

Box Butte County has the 83rd longest season of 93 NE counties, at 163 days against 200 in Richardson County and 127 in Sioux County. Its mean temperature is 47.9°F.

• Morrill County: April 29 to October 13 (167 days, 12 WNV)
• Arthur County: April 30 to October 12 (165 days, 0 WNV)
• Blaine County: May 1 to October 10 (162 days, 1 WNV)
• Thomas County: May 1 to October 10 (162 days, 2 WNV)

West Nile in Box Butte County

From 1999 to 2025, CDC ArboNET counted 43 human West Nile cases in Box Butte County (7 neuroinvasive) across 15 years. The worst was 2003 with 13; the latest was 2025.

See how the dates are worked out, and reading the West Nile counts.