Last frost date

The last frost date is the median date in spring after which the risk of freezing temperatures has mostly passed — our tables use the NOAA 1991–2020 normals at 50% probability. It is the anchor for nearly every spring planting instruction: 'sow peas 5 weeks before last frost, transplant tomatoes 1–2 weeks after.' The 50% figure means half of years see a later freeze — for tender crops, the 10% probability date is the cautious gardener's number.

Median last spring freeze by zone (32°F, 50% probability)

See also: First frost date · Growing season