U.S. Frost Dates
The mean last spring frost and first fall frost for your place, from the 30-year NOAA climate normals at your nearest weather station.
How to read your frost dates
The dates are 30-year means, not deadlines. Tender annuals go out after the last frost date, hardened off and with a eye on the ten-day forecast. The first fall frost is the date after which a hard freeze becomes likely; close pools, drain irrigation, and shut hose bibs before it.
Microclimates matter. A station in a valley can frost later in spring and earlier in fall than one on a nearby ridge. Use the nearest official station as your starting point, then adjust for your own yard's cold pockets, wind exposure, and elevation.
Questions, answered plainly
What is a frost date?
The mean date of the last spring frost and first fall frost at a weather station, averaged over the 30-year climate normal period. It is a planning average, not a guarantee: roughly half of years see frost after the mean spring date, so tender crops usually go out a week or more later.
Why do frost dates matter for my home?
Frost dates set the practical calendar for planting, irrigation blowouts, outdoor faucet shutoffs, pool closing, and the last lawn fertilizer. Using your nearest station instead of a state average can shift these dates by weeks.
What is the frost-free season?
The number of days between the mean last spring frost and the mean first fall frost. In the official NOAA record it ranges from year-round in South Florida and Hawaii to under ninety days in parts of Alaska and the high Rockies.