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Frost dates for Chatham, MA
NOAA weather station USC00191386 at 40 ft elevation. Based on 30 years within 1991-2020. Last verified 2026-10-17.
Last spring freeze (32°F)
Apr 5
median: freeze still happened after this date in half of years
Apr 10 30% risk · Apr 18 10% risk
First fall freeze (32°F)
Nov 15
median: a freeze had happened by this date in half of years
Nov 1 10% chance of a freeze earlier than this
Freeze-free season
221 days
median length between last spring and first fall 32°F freeze
How to read these dates
Spring: a "10% risk" date means NOAA's 1991-2020 data put the chance of a 32°F or colder night after that date at 10%. The "30% risk" date is the convention used by some popular frost calculators (the Old Farmer's Almanac says it uses a 30% probability threshold, source). Fall: a "10%" date means a 10% chance the first freeze comes before it. Source: NOAA readme.
Full table for this station
| Threshold | Spring: latest-freeze date at risk of 10% / 30% / 50% | Fall: first-freeze date at chance of 10% / 50% |
|---|---|---|
| 36°F (frost possible) | May 2 / Apr 24 / Apr 19 | Oct 21 / Nov 2 |
| 32°F (freeze) | Apr 18 / Apr 10 / Apr 5 | Nov 1 / Nov 15 |
| 28°F (hard freeze) | Apr 6 / Apr 1 / Mar 28 | Nov 12 / Nov 26 |
Also at 32°F, last-freeze 70% date Apr 2 and 90% date Mar 27 (frost still likely after these early dates). Data quality: Standard: 24+ years of qualifying data. Source: NOAA NCEI U.S. Climate Normals 1991-2020, station USC00191386, read 2026-10-17.
Is Memorial Day safe here?
Many New England gardeners wait for Memorial Day (it falls between May 25 and May 31). At this station, NOAA's chance of a 32°F or colder night after May 25 is under 10%, and after May 31 is under 10%. Your own spot may differ. See all stations.
UMass Extension says that in many areas of Massachusetts the last frost date is usually around May 15 (read 2026-10-17).
Your planting schedule
Pick how cautious you want to be. The dates apply UNH Extension's per-crop rules (UNH fact sheet, read 2026-10-17) to this station's last-freeze date. UNH's sheet does not say which probability its "last frost" means, so you choose. These are planning dates, not instructions; follow your seed packet and the weather.
Showing the schedule for the 2027 season (dates repeat yearly). Table below defaults to Typical; it updates when you choose.
| Crop | Start seeds indoors | Outdoors | UNH Extension rule used |
|---|---|---|---|
| Spinach | Jan 16 – Feb 20 | Set out Feb 27 – Mar 20 | Start 4-6 wk before set-out; set out 3-6 wk before last frost. |
| Broccoli | Jan 30 – Feb 27 | Set out Mar 13 – Mar 27 | Start 4-6 wk before set-out; set out 2-4 wk before last frost. |
| Brussels sprout | Jan 30 – Feb 27 | Set out Mar 13 – Mar 27 | Start 4-6 wk before set-out; set out 2-4 wk before last frost. |
| Cabbage | Jan 30 – Feb 13 | Set out Mar 13 | Start 4-6 wk before set-out; set out 4 wk before last frost. |
| Kale | Jan 30 – Feb 13 | Set out Mar 13 | Start 4-6 wk before set-out; set out 4 wk before last frost. |
| Kohlrabi | Jan 30 – Feb 13 | Set out Mar 13 | Start 4-6 wk before set-out; set out 4 wk before last frost. |
| Leek | Jan 2 – Jan 16 | Set out Mar 13 | Start 8-10 wk before set-out; set out 4 wk before last frost. |
| Lettuce | Feb 6 – Feb 20 | Set out Mar 13 – Mar 20 | Start 4-5 wk before set-out; set out 3-4 wk before last frost. |
| Onion | Jan 2 – Jan 16 | Set out Mar 13 | Start 8-10 wk before set-out; set out 4 wk before last frost. |
| Radish | — | Sow Mar 13 – Mar 27 | Sow seed in garden 2-4 wk before last frost. |
| Turnip | — | Sow Mar 13 – Mar 27 | Sow seed in garden 2-4 wk before last frost. |
| Parsley | Jan 9 – Jan 23 | Set out Mar 20 – Mar 27 | Start 9-10 wk before set-out; set out 2-3 wk before last frost. |
| Cauliflower | Feb 13 – Feb 27 | Set out Mar 27 | Start 4-6 wk before set-out; set out 2 wk before last frost. |
| Potato | — | Sow Mar 27 – Apr 3 | Plant seed potatoes 1-2 wk before last frost. |
| Swiss chard | Feb 13 – Feb 27 | Set out Mar 27; or sow Mar 13 | Start 4-6 wk before set-out; set out 2 wk before last frost; or sow seed 4 wk before last frost. |
| Bean | — | Sow on/after Apr 10 | Sow seed in garden after last frost. |
| Celery | Jan 16 – Jan 30 | Set out on/after Apr 10 | Start 10-12 wk before set-out; set out after last frost. |
| Parsnip | — | Sow on/after Apr 10 | Sow seed in garden after last frost. |
| Cucumber | Mar 20 – Apr 3 | Set out Apr 17 – Apr 24 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 1-2 wk after last frost; or sow when soil warms to 70°F. |
| Sweet potato | — | Plant slips Apr 17 – Apr 24 | Plant slips (young plants) 1-2 wk after last frost. |
| Tomato | Feb 20 – Mar 13 | Set out Apr 17 – Apr 24 | Start 6-8 wk before set-out; set out 1-2 wk after last frost. |
| Basil | Feb 27 – Mar 13 | Set out Apr 24 | Start 6-8 wk before set-out; set out 2 wk after last frost. |
| Eggplant | Feb 13 – Mar 6 | Set out Apr 24 – May 1 | Start 8-10 wk before set-out; set out 2-3 wk after last frost. |
| Melon | Mar 27 – Apr 3 | Set out Apr 24 | Start 3-4 wk before set-out; set out 2 wk after last frost. |
| Pepper | Feb 13 – Feb 27 | Set out Apr 24 | Start 8-10 wk before set-out; set out 2 wk after last frost. |
| Pumpkin | Mar 27 – Apr 3 | Set out Apr 24 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 2 wk after last frost; or sow when soil warms to 70°F. |
| Summer squash | Mar 27 – Apr 3 | Set out Apr 24 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 2 wk after last frost; or sow when soil warms to 70°F. |
| Winter squash | Mar 27 – Apr 3 | Set out Apr 24 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 2 wk after last frost; or sow when soil warms to 70°F. |
| Zucchini | Mar 27 – Apr 3 | Set out Apr 24 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 2 wk after last frost; or sow when soil warms to 70°F. |
| Rutabaga | — | Sow Jun 15 – Jul 15 | Sow seed in garden mid-June to mid-July (fixed dates, not tied to frost). |
| Beet | — | Sow when soil reaches 45°F (use a soil thermometer) | Sow seed in garden when soil warms to 45°F. |
| Carrot | — | Sow when soil reaches 60°F (use a soil thermometer) | Sow seed in garden when soil warms to 60°F. |
| Corn | — | Sow when soil reaches 60°F (use a soil thermometer) | Sow seed in garden when soil warms to 60°F. |
| Pea | — | Sow as soon as soil thaws | Sow seed in garden as soon as soil thaws. |
Fall: when the garden ends
At this station the median first 32°F freeze is Nov 15; there is a 10% chance of one before Nov 1. Tender crops (tomatoes, peppers, basil) can be damaged at 33-36°F (Almanac.com notes some plants are damaged in that range); the 36°F first-frost date here is median Nov 2 and 10% date Oct 21. UNH Extension notes many fall vegetables tolerate mild frosts down to about 28°F (median first 28°F here: Nov 26), and that row covers can extend the season. UNH: Fall vegetable gardening, read 2026-10-17.
Your garden is not the weather station
This station sits at 40 ft. UNH Extension says first-freeze dates vary "even between relatively close locations, based on factors such as elevation" (source), and notes that gardeners who keep garden journals can use their own records. Gardeners on Reddit describe the same thing: elevation and cold spots change when they can plant (for example r/vermont). Treat these dates as a starting point.
Nearby stations
- Chatham Muni AP, MA: 3 mi away, 68 ft elevation, median last 32°F freeze Apr 13
- Hyannis Barnstable Muni AP, MA: 17 mi away, 55 ft elevation, median last 32°F freeze Apr 22
- Hyannis, MA: 18 mi away, 60 ft elevation, median last 32°F freeze Apr 16
- Nantucket Mem AP, MA: 28 mi away, 45 ft elevation, median last 32°F freeze Apr 13
- Edgartown, MA: 34 mi away, 30 ft elevation, median last 32°F freeze Apr 17