About Frost Date Math

Frost Date Math is a small independent site run by Tam Vu. It exists to answer one kind of question well: when the last spring freeze and first fall freeze usually happen near you, and when to start seeds indoors and move transplants out, using NOAA's 1991-2020 climate normals and university extension guidance.

How the content is made

• Calculators use published formulas and show their assumptions next to the result, so you can check the math yourself.
• Charts and tables come from public sources (extension services, government agencies, manufacturers). Every table names its source and links to it.
• Guides are written and checked by a person. Writing tools may help with drafting, but every number on this site is traced back to a source or to a formula you can see.

Corrections

If you find a mistake, please tell us through the contact page. Corrections are made quickly and the page's "last updated" date changes when they are.

Advertising

This site is free to use and is supported by ads. Ads never change what a calculator says or what a guide recommends.