United States: frost dates by city

The average last spring frost and first autumn frost in 3 cities of United States, from ten years of weather. The last spring frost comes earliest in New York and latest in Denver.

Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.