Mosquito season in Graham County, AZ: when it starts and ends
Mosquito months in Graham County
In a normal year mosquito season in Graham County, AZ starts around March 13 and ends around November 16, about 35 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Graham County, and when
- Start tipping out standing water weekly by February 27.
- Book any yard treatment for mid March, ahead of the July peak.
- Repellent can go away after November 16.
- 6 West Nile cases since 2016 (last 2025): you should use repellent at dusk May to September, more so if over 60.
Graham County against the rest of AZ
Graham County has the 8th longest season of 15 AZ counties, at 248 days against 364 in Maricopa County and 150 in Coconino County. Its mean temperature is 64.8°F.
- Santa Cruz County: February 23 to November 30 (280 days, 2 WNV)
- Pima County: March 6 to November 21 (260 days, 142 WNV)
- Cochise County: March 27 to November 13 (231 days, 4 WNV)
- Yavapai County: April 13 to October 31 (201 days, 7 WNV)
West Nile in Graham County
From 1999 to 2025, CDC ArboNET counted 31 human West Nile cases in Graham County (17 neuroinvasive) across 10 years. The worst was 2010 with 9; the latest was 2025.
More: how the dates are worked out · reading the West Nile counts.