When is the last frost date in my area?
The median last frost date varies by county and elevation, ranging from late February in the Deep South to mid-June in the Northern Rockies. The actual date in any given year can vary by 4-6 weeks from the median because frost timing is naturally variable. Use the conservative bound (the date 9 of 10 years are past their last frost) for unprotected transplants.
Look up your specific county on our frost-date pages — every US county has a NOAA-derived probability table showing the full range of historical frost dates at three temperature thresholds (28°F killing, 32°F light, 24°F hard). Microclimate within a county can shift dates 2-4 weeks, so adjust based on your elevation, slope, and proximity to water. State crop calendars also include county-relevant frost timing for individual crops.