Planting Dates by ZIP Code
Enter your ZIP code for your last spring frost, first fall frost, and a personalized planting calendar — computed from 30 years of NOAA climate data (1991–2020), not a generic zone map.
1. Enter your ZIP code
Enter a valid 5-digit US ZIP code.
We detect your approximate location automatically — or type any ZIP code to plan for that area.
2. Your frost dates
3. Your planting calendar
| Vegetable | Method | Plant from | Harvest ~ | Status |
|---|
Fetching 30 years of NOAA climate data for your ZIP…
How to use the planting dates calculator
Type any US ZIP code above and press Get my dates. The calculator converts your ZIP to its exact coordinates, pulls 30 years of daily minimum temperatures (1991–2020 NOAA data) for that location, and computes three things: your last spring frost, your first fall frost, and a planting calendar for 37 vegetables timed to your climate.
You do not need to create an account, enter an email, or pay anything. The tool is free, and the climate data behind it comes from the same NOAA records that university extension services use.
Why frost dates matter more than a zone number
The USDA hardiness zone tells you which perennial plants survive your coldest winter — it was designed for trees and shrubs. For annualvegetables, what actually decides success is the length of your frost-free season and the date your last spring frost falls. A gardener in zone 7b in coastal North Carolina and one in zone 7b in New Mexico have very different planting windows.
This calculator gives you the dates directly, computed from 30 years of observed temperatures at the coordinates of your ZIP — not a general zone average.
Reading the probabilities: 10%, 50%, and 90%
Frost does not arrive on a schedule. Over 30 years of records, the last spring frost in one city might fall on March 20 one year and April 25 the next. Instead of guessing one date, we show three:
- 10%: the date by which frost has ended in only 3 of 30 years. Planting tender crops this early is a gamble.
- 50% (median): the midpoint — half of the years the last frost is earlier, half later. Good for semi-hardy crops with some frost tolerance.
- 90%: in 27 of 30 years, frost is over by this date. This is the "safe" date for tomatoes, peppers, squash, and other frost-tender crops.
The calendar uses these rules: tender crops go in after the 90% date, semi-hardy crops after the 50% date, and hardy crops can be sown about four weeks before it.
What to plant when: a quick reference by frost tolerance
The full 37-vegetable table updates automatically with your ZIP. Here is the general pattern:
| Tolerance | Examples | Plant after |
|---|---|---|
| Hardy | Beets, carrots, kale, peas, spinach, turnips | 4 weeks before the 50% last frost |
| Semi-hardy | Lettuce, broccoli, cabbage, cauliflower | 50% last frost date |
| Tender | Tomatoes, peppers, eggplant, squash, cucumbers, beans, corn | 90% last frost date |
Crops with long days to maturity (parsnips, sweet potatoes, winter squash, Brussels sprouts) need an early start or a shorter-season variety where the growing season is short — the calendar flags these as "Tight."
Frequently asked questions
How accurate are these planting dates?
The frost dates are computed from 30 years of observed daily minimum temperatures (NOAA 1991–2020 normals) at your ZIP's coordinates — the same source university extension services use. Percentiles describe real year-to-year variation. Local microclimate (elevation, proximity to water, urban heat) can shift dates by a week or two in either direction.
What counts as a frost in this calculator?
A frost event is any day with a minimum temperature at or below 32 °F (0 °C). We scan all 30 years of daily minima, find the last spring frost and first fall frost for each year, and report the 10th, 50th, and 90th percentiles.
Why is my growing season different from the zone map?
Hardiness zones measure average annual extreme minimum temperature — a winter statistic. The growing season measures the frost-free window between spring and fall frosts. Two cities in the same zone can have seasons that differ by weeks, which is why this calculator uses your actual location data.
Do these dates work for container gardening?
Yes — frost dates apply the same way to containers, with two caveats: containers freeze faster than in-ground beds (protect roots earlier), and they warm up faster in spring, so tender crops can often go out a few days earlier if a frost is not forecast.
What if I live where it never freezes?
For ZIPs with no frost events in 30 years of records (south Florida, coastal California, Hawaii), the calculator reports a year-round growing season and shifts the calendar to "plant any time" for most crops.
Methodology & sources
This calculator uses the NOAA 1991–2020 climate normals (via the open-meteo archive API) for your ZIP code's coordinates: every daily minimum temperature for 30 years is scanned for frost events (≤32 °F). The last spring frost and first fall frost are collected per year, then the 10th, 50th, and 90th percentiles give you the "early / median / safe" dates — the same probabilistic approach used by university extension services.
- ZIP → coordinates: zippopotam.us (USPS ZIP data)
- Climate: NOAA 1991–2020 daily minima via open-meteo archive API
- Days to maturity: University of Maryland Extension, Cornell Cooperative Extension, USDA
- Frost rules: tender = after 90% last frost; semi = after 50%; hardy = 4 weeks before
Dates are estimates based on 30-year averages, not guarantees. Local microclimate, elevation, and year-to-year weather always matter. For USDA hardiness zones, always confirm against the official USDA Plant Hardiness Zone Map.