What is a frost date?

A frost date is the average calendar date when air temperature reaches 32°F (0°C) at ground level. The last spring frost date is the typical final freeze of spring; the first fall frost date is the typical first freeze of autumn. These are statistical averages based on decades of weather records.

How accurate are these dates?

The dates are long-term averages derived from USDA and NOAA climate data. In any given year, actual frost can occur 2–4 weeks earlier or later. Always check local forecasts and consider your specific microclimate.

What is a USDA Hardiness Zone?

USDA Plant Hardiness Zones divide the US into 13 zones (1–13) based on the average annual minimum winter temperature, each split into a and b sub-zones of 5°F. Zone 1a is the coldest; zone 13b the warmest.

Why does my city show different dates from my neighbors?

Frost dates vary with elevation, proximity to water, urban heat islands, and local topography. City data reflects the official weather station for that city, which may not match your exact garden location.

What does "growing season" mean?

The growing season is the number of days between the average last spring frost and the average first fall frost — the window when frost-sensitive plants can survive outdoors.

Can I grow vegetables outside my recommended window?

Yes, with protection. Row covers, cold frames, and low tunnels extend the season 2–4 weeks on both ends. Hardy crops like kale, spinach, and carrots can survive light frosts even without protection.

Frost Date Calculator

Name: Frost Date Calculator
Availability: InStock
Author: Nham Vu

Select your USDA hardiness zone or a major US city to get average last spring frost, first fall frost, growing season length, and planting windows for 6 common vegetables.

Find Frost Dates

USDA Hardiness Zone

Not sure of your zone? Check the USDA zone map.

Select a zone or city, then click Calculate to see frost dates.

Last Spring Frost

First Fall Frost

Growing Season

frost-free days

Season Timeline

JanAprJulOctDec

Frost risk Frost-free growing window

Planting Guide for Common Vegetables

Vegetable	Start Indoors	Transplant / Direct Sow	Note

All dates are approximate historical averages. Actual frost dates vary by year and local microclimate. Consult your local cooperative extension office for the most accurate guidance.

Summary

Select your USDA hardiness zone or a major US city to get average last spring frost, first fall frost, growing season length, and planting windows for 6 common vegetables.

How it works

Choose lookup method: by USDA Hardiness Zone (1a–13b) or by state and city.
Select your zone or locate your state then choose a city from the list.
Click "Calculate Frost Dates" to see results.
The tool shows average last spring frost date, first fall frost date, and total growing season days.
A planting guide lists safe direct-sow and transplant windows for 6 common vegetables.
All dates are approximate historical averages — confirm with your local extension office.

Use cases

Determine when it is safe to transplant tomatoes and peppers outdoors.
Plan succession planting windows for cool-season crops like peas and lettuce.
Estimate how many frost-free days are available for long-season crops.
Decide when to start seeds indoors before the last spring frost.
Plan fall planting of cold-tolerant crops before the first fall frost.
Educate students or beginning gardeners about frost risk by region.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu