Frost Date Finder

Find your typical last spring frost and first autumn frost dates for better garden planning. Based on 1981-2010 climate data.

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Your Frost Dates

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How to Use This Tool

1. Choose Your Location

Click anywhere on the map to place a marker, or select a city from the dropdown. The map uses OpenStreetMap tiles and all calculations happen in your browser - no data is sent to our servers.

2. View Your Frost Dates

The tool shows two dates for each season: the "safe" date (recommended for tender crops like tomatoes and peppers) and the "typical" date (median frost date across years).

3. Plan Your Season

Use the safe dates for planning when to transplant tender crops outdoors and when to harvest before frost. The safe growing season tells you how long you have for heat-loving vegetables.

Understanding Frost Dates

Safe dates vs typical dates: The "typical" date is when frost usually ends (spring) or begins (autumn) - but in half of years, frost occurs later or earlier. The "safe" date uses a more cautious threshold (90th percentile for spring, 10th for autumn) plus a 1-week buffer, giving you a much higher confidence margin.

Air frost threshold: This data uses the standard meteorological definition: minimum air temperature below 0°C at 2 metres height. Ground frost (at soil level) typically occurs slightly earlier/later.

Date ranges shown represent the 10th to 90th percentile - in 80% of years, frost dates fall within this range. The "typical" date is the median (50th percentile).

Safe growing season is calculated from the safe spring date to the safe autumn date. This is your reliable window for warm-season crops that cannot tolerate any frost.

What This Means For Your Garden

Starting Seeds Indoors

Count back 6-8 weeks from the safe spring date to know when to start tomatoes, peppers, and other tender crops indoors.

Transplanting Outdoors

Wait until the safe spring date before transplanting tender seedlings. Hardy crops like peas and broad beans can go out earlier.

Autumn Harvest

Have all tender crops harvested or protected by the safe autumn date. Consider succession planting to spread your harvest.

Microclimate Effects

Urban areas, south-facing walls, and sheltered spots may have different frost dates than the regional average shown here.

Note: These dates are based on historical climate data (1981-2010) at 0.5° grid resolution. Actual frost dates vary year to year and can differ from local microclimates. Always check local forecasts during critical planting periods.

Data Source & Attribution

Contains modified Copernicus Climate Change Service information 2019. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.

Data citation: Nobakht, M., Beavis, P., O'Hara, S., Hutjes, R., Supit, I., (2019): Agroclimatic indicators from 1951 to 2099 derived from climate projections. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). DOI: 10.24381/cds.dad6e055

This data is licensed under Creative Commons Attribution 4.0 International (CC-BY-4.0).