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Frost dates for Portland Intl Jetport, ME
NOAA weather station USW00014764 at 45 ft elevation. Based on 30 years within 1991-2020. Last verified 2026-10-17.
Last spring freeze (32°F)
Apr 26
median: freeze still happened after this date in half of years
May 1 30% risk · May 7 10% risk
First fall freeze (32°F)
Oct 15
median: a freeze had happened by this date in half of years
Oct 2 10% chance of a freeze earlier than this
Freeze-free season
170 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 20 / May 12 / May 7 | Sep 24 / Oct 4 |
| 32°F (freeze) | May 7 / May 1 / Apr 26 | Oct 2 / Oct 15 |
| 28°F (hard freeze) | Apr 25 / Apr 19 / Apr 14 | Oct 14 / Oct 27 |
Also at 32°F, last-freeze 70% date Apr 22 and 90% date Apr 16 (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 USW00014764, 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.
UMaine Extension gives central-Maine planting dates and says to plant 10-14 days earlier on the coast and 10-14 days later in northern Maine (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 | Feb 6 – Mar 13 | Set out Mar 20 – Apr 10 | Start 4-6 wk before set-out; set out 3-6 wk before last frost. |
| Broccoli | Feb 20 – Mar 20 | Set out Apr 3 – Apr 17 | Start 4-6 wk before set-out; set out 2-4 wk before last frost. |
| Brussels sprout | Feb 20 – Mar 20 | Set out Apr 3 – Apr 17 | Start 4-6 wk before set-out; set out 2-4 wk before last frost. |
| Cabbage | Feb 20 – Mar 6 | Set out Apr 3 | Start 4-6 wk before set-out; set out 4 wk before last frost. |
| Kale | Feb 20 – Mar 6 | Set out Apr 3 | Start 4-6 wk before set-out; set out 4 wk before last frost. |
| Kohlrabi | Feb 20 – Mar 6 | Set out Apr 3 | Start 4-6 wk before set-out; set out 4 wk before last frost. |
| Leek | Jan 23 – Feb 6 | Set out Apr 3 | Start 8-10 wk before set-out; set out 4 wk before last frost. |
| Lettuce | Feb 27 – Mar 13 | Set out Apr 3 – Apr 10 | Start 4-5 wk before set-out; set out 3-4 wk before last frost. |
| Onion | Jan 23 – Feb 6 | Set out Apr 3 | Start 8-10 wk before set-out; set out 4 wk before last frost. |
| Radish | — | Sow Apr 3 – Apr 17 | Sow seed in garden 2-4 wk before last frost. |
| Turnip | — | Sow Apr 3 – Apr 17 | Sow seed in garden 2-4 wk before last frost. |
| Parsley | Jan 30 – Feb 13 | Set out Apr 10 – Apr 17 | Start 9-10 wk before set-out; set out 2-3 wk before last frost. |
| Cauliflower | Mar 6 – Mar 20 | Set out Apr 17 | Start 4-6 wk before set-out; set out 2 wk before last frost. |
| Potato | — | Sow Apr 17 – Apr 24 | Plant seed potatoes 1-2 wk before last frost. |
| Swiss chard | Mar 6 – Mar 20 | Set out Apr 17; or sow Apr 3 | 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 May 1 | Sow seed in garden after last frost. |
| Celery | Feb 6 – Feb 20 | Set out on/after May 1 | Start 10-12 wk before set-out; set out after last frost. |
| Parsnip | — | Sow on/after May 1 | Sow seed in garden after last frost. |
| Cucumber | Apr 10 – Apr 24 | Set out May 8 – May 15 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 May 8 – May 15 | Plant slips (young plants) 1-2 wk after last frost. |
| Tomato | Mar 13 – Apr 3 | Set out May 8 – May 15 | Start 6-8 wk before set-out; set out 1-2 wk after last frost. |
| Basil | Mar 20 – Apr 3 | Set out May 15 | Start 6-8 wk before set-out; set out 2 wk after last frost. |
| Eggplant | Mar 6 – Mar 27 | Set out May 15 – May 22 | Start 8-10 wk before set-out; set out 2-3 wk after last frost. |
| Melon | Apr 17 – Apr 24 | Set out May 15 | Start 3-4 wk before set-out; set out 2 wk after last frost. |
| Pepper | Mar 6 – Mar 20 | Set out May 15 | Start 8-10 wk before set-out; set out 2 wk after last frost. |
| Pumpkin | Apr 17 – Apr 24 | Set out May 15 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 | Apr 17 – Apr 24 | Set out May 15 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 | Apr 17 – Apr 24 | Set out May 15 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 | Apr 17 – Apr 24 | Set out May 15 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 Oct 15; there is a 10% chance of one before Oct 2. 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 Oct 4 and 10% date Sep 24. UNH Extension notes many fall vegetables tolerate mild frosts down to about 28°F (median first 28°F here: Oct 27), 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 45 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
- West Buxton 2 NNW, ME: 16 mi away, 220 ft elevation, median last 32°F freeze May 7
- Gray, ME: 17 mi away, 378 ft elevation, median last 32°F freeze Apr 28
- Hollis, ME: 19 mi away, 304 ft elevation, median last 32°F freeze May 14
- Kennebunkport, ME: 22 mi away, 20 ft elevation, median last 32°F freeze May 9
- Poland, ME: 25 mi away, 570 ft elevation, median last 32°F freeze May 3