Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 04768 — Portage, ME

ZIP code 04768 (Portage, Aroostook County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is June 2 and the first fall frost September 15.

Where ZIP 04768 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone4a−30 to −25 °F

Coldest night−34.4 to −31.7 °C

Last frostJun 2

First frostSep 15

2012 zone3b

Was 3b on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Portage, ME…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Portage, ME

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostJune 2median — 50% chance of a later frost

Safe for tender plantsJune 21only 10% chance of frost after

First fall frostSeptember 15median — 10% chance by Aug 29

Growing season102 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 20 and returns around September 29.

From the NOAA station Allagash, ME — 20 miles away, elevation 597 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 04768

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 21 – May 5

SpinachSow outdoors · Apr 21 – May 12

Broccoli, cabbageStart indoors · Mar 24 – Apr 7

Broccoli, cabbageTransplant · May 12 – May 26

Onion setsPlant outdoors · May 5 – May 19

PotatoesPlant outdoors · May 12 – May 26

LettuceSow outdoors · May 5 – May 19

Carrots, beetsSow outdoors · May 12 – May 26

TomatoesStart indoors · Apr 7 – Apr 21

TomatoesTransplant · Jun 9 – Jun 23

Peppers, eggplantStart indoors · Mar 24 – Apr 7

Peppers, eggplantTransplant · Jun 16 – Jun 30

BeansSow outdoors · Jun 9 – Jun 23

Sweet cornSow outdoors · Jun 9 – Jun 23

Cucumbers, squashSow outdoors · Jun 9 – Jun 23

Fall lettuce, spinachSow outdoors · Jul 21 – Aug 4

GarlicPlant cloves · Sep 1 – Oct 6

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 2) and first fall frost (Sep 15) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 04768 came on May 5 — about the same time as the 1991–2020 average (May 7).

average
May 72026
May 5

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 4a in Maine

387 plants native to the lower 48 states, recorded in Maine, and rated by the USDA to survive −30 °F or colder — the bottom of zone 4a. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Portage, ME.

Soil in Portage, ME

The soil mapped at the center of ZIP 04768 is Chesuncook — highly decomposed plant material, moderately well drained.

TextureHighly decomposed plant materialtop layer

DrainageModerately well drainednatural drainage class

Organic matter53%high

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classNot prime farmlandUSDA classification

Map unit: Chesuncook-Elliottsville association, 15 to 35 percent slopes, very stony.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 04768; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Portage, ME

Summer high77 °Faverage high, July

Winter low−6 °Faverage low, January

Hot days2days a year at 90 °F or more

Freezing nights218nights a year at 32 °F or less

Growing degree days1,392base 50 °F — the season’s usable heat

Longest day15 h 52 mindaylight on June 21

Shortest day8 h 32 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation37.5 inper year, rain and melted snow

Snowfall100 inper year; 146 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Allagash, ME (20 mi away); precipitation: Allagash, ME (20 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

3 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

047744b

Saint Francis, ME · 23 mi

047394a

Eagle Lake, ME · 25 mi

047373b

Clayton Lake, ME · 25 mi

047434b

Fort Kent, ME · 29 mi

047324a

Ashland, ME · 31 mi

047814a

Wallagrass, ME · 32 mi

047754a

Sheridan, ME · 32 mi

047444a

Fort Kent Mills, ME · 38 mi

Maine planting zones →

Questions about 04768

What planting zone is ZIP code 04768?

ZIP code 04768 (Portage, ME) is in USDA hardiness zone 4a on the 2023 map: the coldest night of an average winter reaches −30 to −25 °F (−34.4 to −31.7 °C).

When is the last frost in Portage, ME?

The median last spring frost (32 °F) near 04768 is June 2; after June 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Allagash station.

When is the first frost in Portage, ME?

The median first fall frost near 04768 is September 15, giving a median frost-free growing season of 102 days.

When should I plant tomatoes in 04768?

Start tomato seeds indoors around Apr 7 – Apr 21 and set transplants outside around Jun 9 – Jun 23, one to three weeks after the median last frost.

How much rain and snow does 04768 get?

About 37.5 inches of precipitation a year and 100 inches of snowfall (NOAA 1991–2020 normals, Allagash station).

How hot do summers get in Portage, ME?

The average high peaks at 77 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 04768 have?

The USDA soil survey maps Chesuncook at the center of ZIP 04768: highly decomposed plant material, moderately well drained.

Did spring come early in Portage, ME in 2026?

Spring leaf-out near 04768 came on May 5 in 2026, about the same as the 1991–2020 average (May 7), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Portage, ME?

Long-day onions: the longest day near 04768 is 15 h 52 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 04768 change?

Yes. The 2012 USDA map put 04768 in zone 3b; the 2023 map puts it in zone 4a. The newer map uses 1991–2020 data and more weather stations.