Garden planning · 114 cities · 20 years of history
Last and First Frost Dates
Pick a city for its average last spring frost and first fall frost, the earliest and latest dates on record, the length of the frost-free season, an estimated hardiness zone, and any frost in this week's forecast.
An average last frost is a coin toss, not a safe date. For frost-tender plants, go by the latest date on record, shown on each city page.
Australia
Canada
United Kingdom
- BirminghamEngland
- BradfordEngland
- BrightonEngland
- BristolEngland
- CambridgeEngland
- CoventryEngland
- LeedsEngland
- LeicesterEngland
- LiverpoolEngland
- LondonEngland
- ManchesterEngland
- Newcastle upon TyneEngland
- NottinghamEngland
- OxfordEngland
- SheffieldEngland
- SouthamptonEngland
- BelfastNorthern Ireland
- EdinburghScotland
- GlasgowScotland
- CardiffWales
United States
- AnchorageAlaska
- PhoenixArizona
- TucsonArizona
- Little RockArkansas
- FresnoCalifornia
- Los AngelesCalifornia
- OaklandCalifornia
- SacramentoCalifornia
- San DiegoCalifornia
- San FranciscoCalifornia
- San JoseCalifornia
- AspenColorado
- Colorado SpringsColorado
- DenverColorado
- PuebloColorado
- JacksonvilleFlorida
- MiamiFlorida
- OrlandoFlorida
- TampaFlorida
- AtlantaGeorgia
- HonoluluHawaii
- MauiHawaii
- BoiseIdaho
- ChicagoIllinois
- IndianapolisIndiana
- Des MoinesIowa
- WichitaKansas
- LouisvilleKentucky
- New OrleansLouisiana
- BaltimoreMaryland
- BostonMassachusetts
- DetroitMichigan
- MinneapolisMinnesota
- Kansas CityMissouri
- St LouisMissouri
- OmahaNebraska
- Las VegasNevada
- AlbuquerqueNew Mexico
- BuffaloNew York
- New YorkNew York
- CharlotteNorth Carolina
- RaleighNorth Carolina
- BismarckNorth Dakota
- CincinnatiOhio
- ClevelandOhio
- ColumbusOhio
- TulsaOklahoma
- PortlandOregon
- PhiladelphiaPennsylvania
- PittsburghPennsylvania
- SwitzerPennsylvania
- ProvidenceRhode Island
- CharlestonSouth Carolina
- AkaskaSouth Dakota
- MemphisTennessee
- NashvilleTennessee
- AustinTexas
- DallasTexas
- Fort WorthTexas
- HoustonTexas
- San AntonioTexas
- Salt Lake CityUtah
- RichmondVirginia
- SeattleWashington
- SpokaneWashington
- MadisonWisconsin
- MilwaukeeWisconsin
Hardiness zones by coldest night
The USDA method: average each year's lowest temperature, then read off the zone. Each zone splits into a (the colder 5°F) and b (the warmer 5°F).
| Zone | Coldest night, °F | °C |
|---|---|---|
| 1 | -60 to -50°F | -51 to -46°C |
| 2 | -50 to -40°F | -46 to -40°C |
| 3 | -40 to -30°F | -40 to -34°C |
| 4 | -30 to -20°F | -34 to -29°C |
| 5 | -20 to -10°F | -29 to -23°C |
| 6 | -10 to 0°F | -23 to -18°C |
| 7 | 0 to 10°F | -18 to -12°C |
| 8 | 10 to 20°F | -12 to -7°C |
| 9 | 20 to 30°F | -7 to -1°C |
| 10 | 30 to 40°F | -1 to 4°C |
| 11 | 40 to 50°F | 4 to 10°C |
| 12 | 50 to 60°F | 10 to 16°C |
| 13 | 60 to 70°F | 16 to 21°C |
Questions
How are these frost dates worked out?
From 20 years of daily minimum temperatures in the Open-Meteo weather archive for each city. A frost is any day whose low falls below 32°F (0°C). The last spring frost is the last such day before midsummer and the first fall frost the first one after it, averaged across every complete year. Southern-hemisphere cities use the southern seasons.
Is it safe to plant on the average last frost date?
Not quite: an average means a frost still comes later in roughly half of years. Each city page shows the latest last frost in the record as well as the average, and frost-tender plants are safer after that later date, or with cover ready.
What is a hardiness zone?
A band based on how cold the coldest night of the year usually gets, which decides which perennials survive winter. The USDA map, also widely used in Canada, the UK and Australia, splits it into 10°F zones and 5°F half zones. The zones on these pages are our estimate from the same archive data, not the official map.
Why does my garden get frost when the forecast low is above freezing?
Air temperature is measured about 2 metres up. On clear, still nights the ground and plants can cool several degrees below that, so ground frost forms even when the reported low is a little above 32°F.