How to Find Your First and Last Frost Dates
- frost-dates
- planning
- beginners
If you only learn two dates as a gardener, make them your last spring frost and first fall frost. Nearly every planting decision — when to sow, transplant, and harvest — is counted from one of them. Here’s how to find yours and put them to work.
What frost dates actually mean
- Last spring frost date — the average date after which you’re unlikely to get a frost. It marks the start of the frost-free growing season.
- First fall frost date — the average date when frost typically returns, ending the season for tender crops.
- Growing season length — the number of frost-free days between them. This tells you whether a long-season crop (like watermelon or certain tomatoes) even has time to mature where you live.
One crucial caveat: these are averages, not guarantees. A “last frost date” of May 10 means roughly half of years see a later frost. Treat it as a planning anchor, not a promise — and keep row cover handy for surprise cold snaps.
How to find your frost dates
The fast way: open Garden Pro Planner, set your location, and your local frost dates are filled in automatically — then the whole planting calendar is built around them.
The manual way:
- Look up your dates by ZIP code through NOAA’s climate data or the National Gardening Association’s frost-date tool.
- Your regional cooperative extension service also publishes local averages — often the most accurate for your microclimate.
- Ask experienced neighbors. Local knowledge captures valley cold pockets and coastal warmth that broad data can miss.
Using frost dates to plan planting
Once you know your last spring frost, you can time everything by counting from it:
| Crop type | When to act | Example (last frost May 10) |
|---|---|---|
| Cool-season (peas, spinach, lettuce) | 4–6 weeks before last frost | Late March – mid April |
| Warm-season starts (tomatoes, peppers) | Sow indoors 6–10 weeks before | Early – mid March |
| Warm-season transplant | After last frost | After May 10 |
| Direct-sow tender crops (beans, squash) | After soil warms, post-frost | Mid – late May |
In late summer, your first fall frost works the same way in reverse: count back each crop’s “days to maturity” from that date to find the last safe sowing date for a fall harvest.
A few practical tips
- Know your microclimate. A south-facing slope, a spot near a heat-retaining wall, or a low frost pocket can shift your real dates by a week or two from the published average.
- Watch the soil, not just the calendar. Warm-season crops sulk in cold soil even after the frost date. Wait for consistent 60°F+ soil before transplanting tomatoes and peppers.
- Keep protection ready. Row cover, cloches, or old bedsheets can save tender plants from a late-spring or early-fall frost and buy you extra weeks at both ends of the season.
The bottom line
Find your last spring and first fall frost dates, then count forward and backward from them to schedule every crop. It turns “when do I plant this?” from a guess into a plan.
Garden Pro Planner does the counting for you — set your location once, and it maps out seed-starting, transplant, and harvest dates for 225+ plants around your exact frost dates.