First and Last Frost Dates by ZIP Code 2026
Find your frost dates so that you can accurately plan and protect your garden. Dates are extracted from the same reliable data used to create the USDA Hardiness Zones.
Frost (36°F) — recommended for planting plans
Recommended for planting plans
Why use frost dates
- Planting dates are specified in weeks before or after average last frost.
- Knowing your dates keeps you informed of risk and ready to protect your plants.
How these dates are calculated
- The last date: last chance of Frost (36°F) for the winter/spring season
- The first date: first chance of Frost (36°F) for the fall/winter season
- 50% chance over the last 10 years
- We use the same dataset that was used to compile the USDA Hardiness Zone Map.
See also Hardiness Zones map.
Frost date FAQs
Diggin Up does not look up the nearest weather station and treat that as your frost date.
Our data starts with weather station readings; however since weather stations can be very far away, mathematical models calculate the effects of elevation and terrain, and produce a more appropriate figure for all nearby locations.
The models capture local terrain and elevation differences better than a distant station, at roughly 2.5 miles (4 km) resolution.
Yard-scale effects—a warm south wall, a frost pocket, urban heat, or wind shelter—are finer than that grid. Use these dates as a planning baseline, then check local forecasts and what you know about your own site.
Frost (36°F) is the planning default for last and first frost dates. Freeze (32°F) and Hard freeze (28°F) are colder risk thresholds when you want more conservative freeze guidance.
Use Compare thresholds above the results to switch which temperature the tool uses for the dates you see.
Frost typically forms on clear, calm nights when heat radiates from the ground into the atmosphere, most often in spring and fall.
Cloudy or windy nights mix warmer air and usually reduce frost risk even when the calendar looks similar.
Yes. Frost dates are historical averages at a given probability, not a guarantee that frost will not return.
Always check your local forecast before planting tender crops or removing season protection.
ZIP codes can span enough elevation and terrain that frost dates differ by several days from one spot to another.
Fact: 99557 in Alaska is a whopping 13,590 square miles!
Enter your current location in the calculator location and we will pull the most localized data for your estimation.
Cool-season and cold-hardy crops—such as peas, spinach, radishes, carrots, onions, and lettuce—are often sown or set out before the average last frost.
Tender warm-season plants (tomatoes, peppers, cucumbers, basil, and most annual flowers) wait until after the last frost date for your chosen threshold.
Growing season length is the span of days between the last spring frost and the first fall frost for a given temperature threshold.
A longer frost-free window means more time for warm-season crops; a shorter one favors cool-season plantings and season-extension techniques.
No. USDA hardiness zones describe winter cold extremes that perennial plants must survive.
Frost dates mark the typical start and end of the frost-free growing season for annual planting and protection—season bookends, not the same as your zone number.
See also Hardiness Zones map.