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

Mosquito months in Valencia County

In a normal year mosquito season in Valencia County, NM starts around April 8 and ends around October 31, about 29 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 Valencia County, and when

• Start tipping out standing water weekly by March 25.
• Book any yard treatment for early April, ahead of the July peak.
• Repellent can go away after October 31.
• 20 West Nile cases since 2016: you should wear EPA-registered repellent at dusk June to August, and check NM spray notices.

Valencia County against the rest of NM

Valencia County has the 16th longest season of 33 NM counties, at 206 days against 268 in Doña Ana County and 114 in Catron County. Its mean temperature is 56.2°F.

• Roosevelt County: April 7 to November 1 (208 days, 3 WNV)
• Curry County: April 8 to November 2 (208 days, 3 WNV)
• Otero County: April 20 to October 30 (193 days, 3 WNV)
• San Juan County: April 17 to October 25 (191 days, 49 WNV)

West Nile in Valencia County

From 1999 to 2025, CDC ArboNET counted 47 human West Nile cases in Valencia County (31 neuroinvasive) across 17 years. The worst was 2003 with 11; the latest was 2025.

Background: reading the West Nile counts; how the dates are worked out.