About Frost Report

Frost dates and planting calendars for 6,476 places across the United States, worked out from public weather records.

Where the dates come from

Every page uses one weather station from NOAA's 1991–2020 U.S. Climate Normals, the official 30-year averages from the National Centers for Environmental Information. For stations with freeze records, NOAA publishes the date of the last spring and first fall freeze that is passed in 1, 5 and 9 years out of 10, at 32°F and at 28°F. Those are the dates on each page.

Each zip code goes to its nearest station with freeze records, using the Census Bureau's zip code areas (ZCTAs). Each page is named after the biggest town near its station, using Census place names and population estimates. Where a zip code is more than 30 miles from its station, the page says so.

How the planting calendar works

The calendar covers 20 common vegetables. Each crop's dates are counted in weeks from the page's own frost dates, following common university extension advice. Cool-season crops count from the typical last frost, since a light frost won't hurt them. Warm-season crops wait for the date by which frost is over in 9 years out of 10. Where the frost-free season is usually too short for a crop, the page says so instead of giving dates.

Limits worth knowing

• These are 30-year averages. Recent springs have tended to warm earlier than the averages suggest.
• Your garden can differ from the station: hills, valleys, cities and big lakes all change frost by days or weeks.
• Frost is about air temperature. Soil temperature, rain and the variety you grow matter too. Your local extension service can fine-tune dates for your area.

Who runs it

This is an independent site, not part of NOAA or the Census Bureau. The pages are generated by code from public data, so every place gets the same careful method.