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

Mosquito months in Bernalillo County

In a normal year mosquito season in Bernalillo County, NM starts around March 31 and ends around November 1, about 31 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 Bernalillo County, and when

• Start tipping out standing water weekly by March 17.
• Book any yard treatment for late March, ahead of the July peak.
• Repellent can go away after November 1.
• 87 West Nile cases since 2016: you should wear EPA-registered repellent at dusk June to August, and check NM spray notices.

Bernalillo County against the rest of NM

Bernalillo County has the 9th longest season of 33 NM counties, at 215 days against 268 in Doña Ana County and 114 in Catron County. Its mean temperature is 56.9°F.

• Chaves County: March 31 to November 6 (220 days, 9 WNV)
• Socorro County: March 31 to November 3 (217 days, 1 WNV)
• De Baca County: April 3 to November 3 (214 days, 0 WNV)
• Quay County: April 4 to November 4 (214 days, 6 WNV)

West Nile in Bernalillo County

From 1999 to 2025, CDC ArboNET counted 175 human West Nile cases in Bernalillo County (109 neuroinvasive) across 19 years. The worst was 2003 with 35; the latest was 2025.

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