NOAA 1991–2020 CLIMATE NORMALS
First and last frost dates
Search by city or ZIP code to find historical spring and fall freeze dates. Compare risk levels and calculate when to start seeds.
Free to explore No account needed NOAA climate data
8,227 local guides3,868 stations · 50 states & districts
30 years of observations1991–2020 climate normals
Three risk levels10%, 30% and 50% probabilities
Frost dates by state
Select a state to compare last spring and first fall freeze dates for the cities we cover.
Explore all locationsTYPICAL LAST SPRING FREEZE
Earlier in the yearLater in the year
Map colors summarize the selected stations in each state. Your local dates may differ.
Select a state to view frost dates
Frost dates for US cities
Illinois
Chicago
Last spring freezeApr 10First fall freezeNov 5
209 days between median freezesMassachusetts
Boston
Last spring freezeApr 4First fall freezeNov 9
219 days between median freezesNew York
New York City
Last spring freezeMar 30First fall freezeNov 20
235 days between median freezesMaine
Portland
Last spring freezeApr 26First fall freezeOct 15
172 days between median freezes
Dates shown are historical medians at nearby weather stations, not this year’s forecast.
Seed starting and frost protection guides
GUIDE / 01
FROST DATESHow to read frost dates and freeze probabilities
Understand the 10%, 30% and 50% freeze probabilities, temperature thresholds and local conditions behind a frost date.
Read the guideGUIDE / 02
SEED STARTINGWhen to start seeds indoors
Work backwards from an outdoor planting date to plan your indoor seed-starting window.
Read the guideGUIDE / 03
FROST PROTECTIONHow to protect plants from frost
Check the forecast, cover vulnerable plants and move containers indoors before a cold night.
Read the guide