First Frost Planner
Turn your average first frost date into the dates you plan from. When to start, how early or late frost could really arrive, and how long you have left.
This tool runs in your browser, so it needs JavaScript switched on. Everything below is the tool itself.
Look these up first. The guide below shows you where. Whatever you type stays in this browser.
| Start planning | two weeks before your date |
|---|---|
| Your date | the date you looked up |
| Frost could come this early | three weeks before your date |
| ...or this late | three weeks after your date |
| Cautious anchor | your early-risk date |
| Growing season over | your hard frost date |
A frost date is an average of what happened before, not a forecast of what will happen this year. Keep watching your local forecast as the date gets closer.
The date most sites publish is a 50% date. Frost comes earlier than it in about half of years, so it is a midpoint and not a deadline. Some sources also give a 10% or 30% date. That one is earlier. Use it as your anchor for anything tender or hard to replace. Two sites more than a fortnight apart are usually quoting different thresholds rather than disagreeing.