Frost Date Lookup
Find your first and last frost dates by ZIP code. See your frost-free growing window, season status, and days until the next frost event.
Frost dates are the foundation of garden planning. Your last spring frost tells you when it is safe to transplant tender crops outdoors, and your first fall frost tells you when to harvest or protect cold-sensitive plants. Enter your ZIP code below to get frost date estimates based on your USDA hardiness zone and 30-year NOAA averages.
Data last updated: March 2026
Protect Your Plants From Frost
Frost Protection Covers
Row covers, frost blankets, and plant cloches to protect tender seedlings from late spring frosts and early fall freezes.
Min/Max Garden Thermometers
Track overnight low temperatures to know exactly when frost threatens your garden. Wireless models with indoor display available.
Get Planting Reminders
We'll email you when it's time to start seeds, transplant, and harvest based on your zone. No spam, just seasonal alerts.
Frequently Asked Questions
A frost date is the average date of the last spring frost or first fall frost in your area, based on 30 years of weather data. It matters because frost kills or damages warm-season crops like tomatoes, peppers, squash, and beans. Knowing your frost dates helps you time seed starting, transplanting, and fall harvest protection so you do not lose plants to unexpected freezes.
How This Calculator Works
We look up your USDA hardiness zone using the USDA Plant Hardiness Zone Map API (phzmapi.org) based on your ZIP code, then cross-reference it with 30-year average frost date normals from NOAA. Frost dates are estimates based on the 50% probability date, meaning there is a 50% chance of frost occurring after the last spring frost date and before the first fall frost date. Actual frost dates can vary by 2 to 3 weeks depending on local microclimates, elevation, and weather patterns.
Tips for Working With Frost Dates
- Frost dates are averages, not guarantees. Add a 1 to 2 week safety buffer before transplanting warm-season crops like tomatoes and peppers.
- Microclimates matter. South-facing slopes, urban heat islands, and areas near buildings or water stay warmer longer than open fields at the same ZIP code.
- Use row covers or cold frames to extend your growing season by 2 to 4 weeks on each end, effectively shifting your frost dates.
- Monitor overnight low temperatures as your frost dates approach. Frost can occur when air temperatures drop below 36 F, even if the forecast says 38 F, because ground-level temperatures run colder.
- Once you know your frost dates, use our planting date calculator to plan when to start each vegetable.
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