WeatherArchive / Frost dates
First and last frost dates for your location
When is it safe to plant out tender seedlings, and when should you bring them in? See the typical last spring frost and first autumn frost for any place, with the early and late years, from 30 years of nightly lows.
Reading a frost date properly
A “last frost date” is a median: in half of years the final frost comes later. That is why seed packets and extension services recommend waiting a week or two after it for frost-tender plants such as tomatoes, beans, squash and basil. Hardy crops (peas, broad beans, onions) tolerate light frost and can go in earlier.
The thresholds here follow common US and UK horticultural usage: 0 °C (32 °F) for a light frost that damages tender leaves, −2.2 °C (28 °F) for a moderate freeze that hurts most plants, and −4.4 °C (24 °F) for a hard freeze. Because air a metre or two up is warmer than the ground on clear, calm nights, the 2 °C option estimates ground frost.
Questions people ask
What is the last frost date?
The typical date of the final spring night at or below freezing. Here it is the median across 30 years, with early and late years shown so you can judge the risk.
Can I look up frost dates by zip code or postcode?
Yes: type the postcode or town into the place search. The dates come from the closest model grid cell.
Why does my local extension office give a different date?
They use a station’s own records, often from 1991–2020, and sometimes a different probability level. Reanalysis describes a wider area and can miss cold hollows.
What does “1 in 10” mean?
Only one year in ten had its last spring frost earlier than the early date, and one in ten later than the late date.