Last Frost Day - Showcase Project

Last Frost Day is a free tool for the question every gardener asks each spring: when is it safe to plant? Most frost date sites give one average date, and that date is close to a coin flip, because in about half of years frost comes later than average. Last Frost Day shows the real odds instead. Features: enter any U.S. ZIP code and the site finds the nearest weather station. It shows the last spring freeze and first fall freeze dates as probabilities from 10% to 90%, at three temperature thresholds of 32°F, 28°F and 36°F. Each lookup also shows the USDA plant hardiness zone. Frost data comes from NOAA NCEI U.S. Climate Normals for 1991 to 2020, and zones come from the PRISM Climate Group at Oregon State University. The lookup runs in the browser and returns results instantly. Use cases: planning when to set out tomatoes and peppers, timing seed starting indoors, deciding when to plant cool season crops, working out the length of the growing season, or choosing plants that suit the local hardiness zone. Benefits: gardeners can pick how much risk to accept, for example waiting for a 10% chance of frost for tender plants, rather than relying on one average date. The data is official and recent, and the tool is simple to use. It is free and independent, and not affiliated with NOAA or USDA.