About MosquitoMonths
Why this exists
"When does mosquito season start" gets asked by people with a date in mind: a yard treatment to book, a wedding outside, a trip, a dog's heartworm months. Most answers say "spring" or give one date for a whole state. The real answer moves by months between Minnesota and the Gulf Coast, and it can be worked out for each county from records that already exist. MosquitoMonths does that for 3,140 counties.
Where the numbers come from
Season dates come from NOAA's 1991-2020 US climate normals: monthly mean temperatures and the usual dates of the first and last hard freeze at about 7,000 weather stations, blended to each county. West Nile counts come from CDC ArboNET's county records for 1999 to 2025. The rules that turn temperatures into dates are in how the season dates are worked out, and what the case counts can and cannot tell you is in reading the West Nile counts.
What this site will not tell you
It will not tell you how many mosquitoes are biting in your yard this week. A normal year is a 30-year average; a warm spring, a wet June or a nearby marsh changes this year's numbers. It does not give medical advice, and a West Nile count is a history of reported cases, not a forecast of risk.
Who runs this
MosquitoMonths is an independently run site. It is not affiliated with NOAA, CDC, any health department, pest-control company or repellent maker. If a page ever carries a sponsored link, that is disclosed on the page itself and in the privacy policy.
Written by
Each county page is generated by AI software from the cited NOAA and CDC data - no journalist or editor writes or reviews a page before it publishes. The temperatures, dates and case counts come from those public records, not from AI; the AI only assembles the sentences around them.