In cooler climates knowing your local frost dates is essential for successful growing, helping you time planting, protect vulnerable crops, and extend your growing season. Our Frost Date Calculator provides reliable estimates to guide your decisions.
How we calculate / predict frost dates
Our predictions are based on extensive historical climate data for your location, analyzing long-term average temperatures. Our system uses sophisticated statistical methods to predict minimum temperatures for each day of the year. This allows us to estimate when temperatures are likely to cross critical frost thresholds.
We provide estimated dates for:
- Air Frost: When ambient air temperatures reach freezing 0°C / 32°F, even if only for short periods.
- Light Ground Frost: A milder ground frost where temperatures at ground level reach between 0 and -2°C or 32 to 28°F.
- Hard Ground Frost: A severe ground frost where temperatures at ground level head below -2°C or 28°F for sustained periods.
For each type, you'll receive a single estimated date for the last frost in spring and the first frost in autumn / fall. For regions without typical frost cycles, our tool will indicate whether air and ground temperatures are likely to remain above or below these thresholds.
While no model can perfectly predict daily weather, our calculator offers valuable, data-driven insights to help you grow with greater confidence.
Add Frost Dates to Your Website or App
Give your visitors instant access to frost dates, growing zones, and frost risk timelines.
Embeddable Widget Free
Drop a ready-made frost date calculator into any website with two lines of HTML. Free to use, no credit card required.
Frost Dates API
Build frost dates into your own app with our REST API. Get frost dates, USDA zones, and climate data as JSON.
Free to get started — no credit card required.
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