Frost Date Calculator

Planting schedules live or die by frost timing, and this tool estimates the average first and last frost dates for your location using your USDA Plant Hardiness Zone. Those two dates frame the growing season: the average last frost in Spring 2026 tells you when tender annuals can go in the ground with reasonable confidence, while the average first frost in Fall 2026 marks the deadline for harvesting frost-sensitive vegetables before cold damage sets in.

Behind the dates is historical weather data assembled by the National Oceanic and Atmospheric Administration (NOAA) alongside the USDA Plant Hardiness Zone Map. For each zone, the tool reports the 30% probability date for the last spring frost, meaning roughly a 30% chance that frost still occurs after it, and the 30% probability date for the first fall frost, meaning about a 30% chance frost arrives before it. Both figures come from decades of temperature records, focused specifically on readings at or below 32°F (0°C).

Treat the output as a long-run average rather than a guarantee. Microclimates and any given year's weather can push actual frost earlier or later, so leaning on the average last frost date alone leaves you exposed to a late cold snap. It also helps to keep two related ideas separate: the USDA Plant Hardiness Zone describes average minimum winter temperatures, which is not the same thing as the frost dates this calculator returns.