Frost dates by ZIP code

How we work it out

Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.

The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.

Planting zones come straight from the USDA's 2023 Plant Hardiness Zone Map ZIP code table, the same one behind the USDA's own zone finder. A zone is the average of each year's coldest night from 1991 to 2020, in 10 °F steps, split into 5 °F halves: a and b. It says nothing about summer heat or rain, and it's an average, so some winters go colder.