Rodent Season Checker
By Marcus Ellery, Pest Control Editor · Updated September 2026 · Methodology
One ZIP code gets you the autumn window when nights in your area start freezing, which is the run-up to when house mice look for a warmer wall. The dates come from the 6,948 weather stations that publish NOAA 1991-2020 first-freeze normals. Nationally the typical first freeze spans August 21 to February 1, so a national average would be useless to almost everybody.
What you get back
- The nearest NOAA station with published freeze normals, named, with the distance in miles so you can judge how local the answer is.
- First 32°F night at the 10th, 50th and 90th percentile, plus the average number of freezing nights a year.
- If your ZIP is inside New York City, Chicago, Boston, Washington, Baltimore, Detroit, its three-year 311 rodent complaint total, complaints per square mile, and rank within that city.
- Current 2026 cost ranges for trapping, exclusion and cleanup, straight from the calculator.
What it will not do
It will not tell you whether you have mice. It will not predict this year’s weather, because a 30-year normal describes a climate rather than a forecast. It will not extrapolate past 75 miles from a station, and it will not compare your city’s complaint counts to another city’s, because the two cities are not counting the same event.
If they are already inside
Trapping runs about $150 – $450 nationally; adding exclusion, which is the sealing work that stops the next ones, runs $350 – $1,000.
Frequently asked questions
What does the tool actually look up?
Your ZIP code's Census centroid, then the nearest weather station that publishes NOAA 1991-2020 first-freeze probabilities, capped at 75 miles. It returns that station's name and distance, the 10th, 50th and 90th percentile dates for the first 32°F night, and the average number of nights below freezing a year. If your ZIP falls inside one of the 6 cities whose 311 rodent data we publish, it also returns that ZIP's complaint total and rank inside its own city.
What if there is no station near me?
Then we say so and stop. 115 ZIP codes in the country have no station with published freeze normals within 75 miles. We name the gap rather than stretching a distant station over it, because a freeze date borrowed from 200 miles away is a guess dressed as data.
Is my ZIP code stored?
No. The lookup reads a static file, nothing is written, and the analytics event carries only the first three digits of the ZIP so we can see roughly which regions use the tool. No address, no full ZIP, no personal data.
Why the first freeze rather than a temperature?
Because no extension source we could verify names a temperature at which mice move indoors. UC IPM describes house mice entering homes in autumn as nighttime temperatures become colder, which is a direction and not a threshold. Rather than invent a number, the window is bounded by two published NOAA figures: the early-decile first freeze and the median one.
Does a complaint rank mean my block has rats?
It means people in that ZIP called 311 about rodents more often than people in most other ZIPs of the same city over three years. Reporting habits differ block to block, so a high rank is a signal worth acting on rather than a measurement of the population.