Frost Date Finder (ZIP / Postal Code)
Look up your average last spring frost and first fall frost dates at the 32°F / 0°C freeze threshold; the baseline used for frost-based planting schedules.
Average frost dates by ZIP / postal code
Local frost dates help to time seed starting, outdoor planting, and fall crop planning.
Use these dates as planning anchors, then adjust for real conditions like nighttime lows and soil temperature.
Look Up My Frost Dates
Enter a 5-digit ZIP (U.S.) or the first 3 characters of your postal code (Canada FSA).
Frost dates are averages. Freezing (32°F / 0°C) can occur earlier or later in any given year.
How This Tool Works
This tool maps your ZIP code (U.S.) or postal code prefix (Canada FSA) to the nearest available historical climate normals dataset, then returns typical last spring and first fall frost dates at the 32°F (0°C) threshold.
The output is deterministic: it does not use real-time forecasts, and it does not attempt to predict this year’s frost. It returns typical-year boundary dates that can be used to plan schedules and margin.
Location → Nearest normals dataset → 32°F frost thresholds → 50% probability dates
Mapping is designed to be fast and consistent for a static site. Local terrain and microclimates can shift your true frost experience earlier or later than the regional midpoint, especially in mountainous, coastal, or exposed rural locations.
What To Do With Your Frost Dates
Once you have your frost boundaries, you can convert them into practical planning windows using simple counting logic. Frost dates also define your total frost-free window — the number of days between last and first frost. That window sets the outer limits of what can reasonably mature in a typical year.
- Count backward from last frost to plan indoor seed starts and transplant readiness. Use the Seed Start Planner if you want a crop-specific schedule.
- Count backward from first frost to set fall planting cutoffs and harvest priorities. Use the First Frost Planner to estimate fall cutoffs by crop.
Frost-free days describe the calendar length of your season — but calendar length alone does not guarantee maturity. Temperature determines how quickly crops develop. To evaluate whether your season delivers enough accumulated heat, test your location with the Growing Degree Day Planner.
Accuracy Notes (What This Tool Can and Can't Do)
- Threshold: 32°F / 0°C (freeze).
- Normals-based: uses 1991–2020 climate normals (typical-year baseline).
- Probability framing: 50% midpoint dates, not guarantees.
- Location mapping: ZIPs and FSAs map to nearby climate normals data; local variation still applies.
Practical rule: use frost dates to set your baseline schedule, then apply margin. If your yard tends to frost early (low spots, cold-air drainage, exposed rural sites), plan as if frost arrives 7–14 days earlier.
Final go/no-go decisions should be made using nighttime lows, because microclimates can differ from the regional midpoint even in a typical year.
Frequently Asked Questions
What does “32°F / 0°C” mean?
It’s the freezing point of water. Many seedlings and warm-season crops are damaged at or near this threshold, so it’s a practical boundary for season planning.
Are these dates guarantees?
No. These are typical midpoint dates (50% probability) based on 1991–2020 climate normals. In roughly half of years, frost happens earlier; in the other half, later. If you want higher reliability, plan with buffer.
Why use ZIP/postal code instead of city search?
ZIPs and FSAs are fast to enter and work well with a static dataset (no APIs). If you’re in a mountainous or coastal region, expect more microclimate variation than the regional midpoint suggests.
Does this work in Canada?
Yes. Enter the first 3 characters of your postal code (FSA). Frost boundary logic applies across cold regions in both the U.S. and Canada.