Mosquito season in Santa Cruz County, AZ: when it starts and ends

Mosquito months in Santa Cruz County

In a normal year mosquito season in Santa Cruz County, AZ starts around February 23 and ends around November 30, about 40 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 Santa Cruz County, and when

• Start tipping out standing water weekly by February 9.
• Book any yard treatment for late February, ahead of the July peak.
• Repellent can go away after November 30.
• 2 West Nile cases since 2016 (last 2021): you should use repellent at dusk June to September, more so if over 60.

Santa Cruz County against the rest of AZ

Santa Cruz County has the 6th longest season of 15 AZ counties, at 280 days against 364 in Maricopa County and 150 in Coconino County. Its mean temperature is 64.5°F.

• Yuma County: January 23 to December 11 (322 days, 8 WNV)
• Gila County: February 2 to December 7 (308 days, 9 WNV)
• Pima County: March 6 to November 21 (260 days, 142 WNV)
• Graham County: March 13 to November 16 (248 days, 6 WNV)

West Nile in Santa Cruz County

From 1999 to 2025, CDC ArboNET counted 4 human West Nile cases in Santa Cruz County (1 neuroinvasive) across 4 years. The worst was 2021 with 1; the latest was 2021.

More: how the dates are worked out · when the season starts across the US.