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Frost dates for Houlton Intl AP, ME

NOAA weather station USW00014609 at 476 ft elevation. Based on 29 years within 1991-2020. Last verified 2026-10-17.

Last spring freeze (32°F)

May 27

median: freeze still happened after this date in half of years

Jun 2 30% risk · Jun 10 10% risk

First fall freeze (32°F)

Sep 18

median: a freeze had happened by this date in half of years

Sep 5 10% chance of a freeze earlier than this

Freeze-free season

115 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

ThresholdSpring: latest-freeze date at risk of 10% / 30% / 50%Fall: first-freeze date at chance of 10% / 50%
36°F (frost possible)Jun 28 / Jun 17 / Jun 10Aug 24 / Sep 7
32°F (freeze)Jun 10 / Jun 2 / May 27Sep 5 / Sep 18
28°F (hard freeze)May 28 / May 18 / May 10Sep 18 / Oct 1

Also at 32°F, last-freeze 70% date May 21 and 90% date May 9 (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 USW00014609, 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 50-70%, and after May 31 is 30-50%. 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.

Last-frost reference date

Showing the schedule for the 2027 season (dates repeat yearly). Table below defaults to Typical; it updates when you choose.

CropStart seeds indoorsOutdoorsUNH Extension rule used
SpinachMar 10 – Apr 14Set out Apr 21 – May 12Start 4-6 wk before set-out; set out 3-6 wk before last frost.
BroccoliMar 24 – Apr 21Set out May 5 – May 19Start 4-6 wk before set-out; set out 2-4 wk before last frost.
Brussels sproutMar 24 – Apr 21Set out May 5 – May 19Start 4-6 wk before set-out; set out 2-4 wk before last frost.
CabbageMar 24 – Apr 7Set out May 5Start 4-6 wk before set-out; set out 4 wk before last frost.
KaleMar 24 – Apr 7Set out May 5Start 4-6 wk before set-out; set out 4 wk before last frost.
KohlrabiMar 24 – Apr 7Set out May 5Start 4-6 wk before set-out; set out 4 wk before last frost.
LeekFeb 24 – Mar 10Set out May 5Start 8-10 wk before set-out; set out 4 wk before last frost.
LettuceMar 31 – Apr 14Set out May 5 – May 12Start 4-5 wk before set-out; set out 3-4 wk before last frost.
OnionFeb 24 – Mar 10Set out May 5Start 8-10 wk before set-out; set out 4 wk before last frost.
Radish—Sow May 5 – May 19Sow seed in garden 2-4 wk before last frost.
Turnip—Sow May 5 – May 19Sow seed in garden 2-4 wk before last frost.
ParsleyMar 3 – Mar 17Set out May 12 – May 19Start 9-10 wk before set-out; set out 2-3 wk before last frost.
CauliflowerApr 7 – Apr 21Set out May 19Start 4-6 wk before set-out; set out 2 wk before last frost.
Potato—Sow May 19 – May 26Plant seed potatoes 1-2 wk before last frost.
Swiss chardApr 7 – Apr 21Set out May 19; or sow May 5Start 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 Jun 2Sow seed in garden after last frost.
CeleryMar 10 – Mar 24Set out on/after Jun 2Start 10-12 wk before set-out; set out after last frost.
Parsnip—Sow on/after Jun 2Sow seed in garden after last frost.
CucumberMay 12 – May 26Set out Jun 9 – Jun 16
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 Jun 9 – Jun 16Plant slips (young plants) 1-2 wk after last frost.
TomatoApr 14 – May 5Set out Jun 9 – Jun 16Start 6-8 wk before set-out; set out 1-2 wk after last frost.
Rutabaga—Sow Jun 15 – Jul 15Sow seed in garden mid-June to mid-July (fixed dates, not tied to frost).
BasilApr 21 – May 5Set out Jun 16Start 6-8 wk before set-out; set out 2 wk after last frost.
EggplantApr 7 – Apr 28Set out Jun 16 – Jun 23Start 8-10 wk before set-out; set out 2-3 wk after last frost.
MelonMay 19 – May 26Set out Jun 16Start 3-4 wk before set-out; set out 2 wk after last frost.
PepperApr 7 – Apr 21Set out Jun 16Start 8-10 wk before set-out; set out 2 wk after last frost.
PumpkinMay 19 – May 26Set out Jun 16
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 squashMay 19 – May 26Set out Jun 16
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 squashMay 19 – May 26Set out Jun 16
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.
ZucchiniMay 19 – May 26Set out Jun 16
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.
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 thawsSow seed in garden as soon as soil thaws.

Fall: when the garden ends

At this station the median first 32°F freeze is Sep 18; there is a 10% chance of one before Sep 5. 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 Sep 7 and 10% date Aug 24. UNH Extension notes many fall vegetables tolerate mild frosts down to about 28°F (median first 28°F here: Oct 1), 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 476 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.

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