About and method

Plant By Frost shows frost dates from NOAA climate normals. It is independent and has no link to NOAA.

• Frost dates are the 1991 to 2020 freeze probability dates NOAA publishes for each station, for a low of 32°F (frost), 28°F (hard freeze) and 36°F (light frost).
• The "average" date is NOAA's 50% probability date. The other rows use NOAA's 10% and 90% dates.
• A ZIP code is matched to the nearest station with both spring and fall dates, using the Census Bureau's ZIP area centre points, up to 60 km away. The distance is shown.
• Station names are NOAA's, lightly tidied (for example "AP" becomes "Airport").

Limits

Frost depends on very local conditions. Low spots, valleys and higher ground often freeze later in spring than a nearby station. These are long-run averages, not a forecast.

Corrections

Report a problem and it will be checked against the NOAA file. Changes are dated in the change log.

Sources

1. U.S. Annual/Seasonal Climate Normals, 1991 to 2020 (freeze probability dates by station), NOAA National Centers for Environmental Information, checked 1 November 2026
2. Annual/Seasonal Normals 1991 to 2020 documentation, NOAA National Centers for Environmental Information, checked 1 November 2026
3. 2024 Gazetteer Files, ZIP Code Tabulation Areas, US Census Bureau, checked 1 November 2026