About Frost Date Finder
Public federal data, one page per record, free to read.
What this site publishes
Frost dates and planting windows for every US ZIP code with a population above 2,000 — the last spring freeze, the first autumn freeze, the length of the growing season and the USDA hardiness zone, turned into a calendar of what to do when.
Why it exists
The underlying data is public and free, but it is published for analysts rather than for readers: bulk files, codebooks, and lookup tools that expect you to know the identifier already. This site does the matching and the arithmetic, then states the answer in a sentence at the top of the page.
Where the figures come from
Climate normals published by NOAA for 1991-2020, matched to each ZIP code by the nearest reporting station, and plant hardiness zones from the USDA.
Nothing here is estimated, modelled or generated. Every number traces to a published federal record.
What it is not
A normal is a thirty-year average, not a forecast. Any individual year can freeze two to three weeks either side of these dates, so check the actual forecast before planting out.
Corrections
If a page contradicts the official source, the official source is right and we want to know. Write to us from the contact page.