Mosquito season in Doña Ana County, NM: when it starts and ends

Mosquito months in Doña Ana County

In a normal year mosquito season in Doña Ana County, NM starts around February 26 and ends around November 21, about 38 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 Doña Ana County, and when

• Start tipping out standing water weekly by February 12.
• Book any yard treatment for late February, ahead of the July peak.
• Repellent can go away after November 21.
• 26 West Nile cases since 2016: you should wear EPA-registered repellent at dusk May to September, and check NM spray notices.

Doña Ana County against the rest of NM

Doña Ana County has the 1st longest season of 33 NM counties, at 268 days against 268 in Doña Ana County and 114 in Catron County. Its mean temperature is 62.8°F.

• Sierra County: March 1 to November 20 (264 days, 0 WNV)
• Eddy County: March 5 to November 18 (258 days, 5 WNV)

West Nile in Doña Ana County

From 1999 to 2025, CDC ArboNET counted 102 human West Nile cases in Doña Ana County (65 neuroinvasive) across 22 years. The worst was 2007 with 14; the latest was 2025.

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