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

Planting zone for 04068 — Porter, ME

ZIP code 04068 (Porter, Oxford County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 12 and the first fall frost October 1.

Where ZIP 04068 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.

Zone5a−20 to −15 °F
Coldest night−28.9 to −26.1 °C
Last frostMay 12
First frostOct 1
2012 zone5a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Porter, 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 Porter, ME

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 12median — 50% chance of a later frost
Safe for tender plantsMay 25only 10% chance of frost after
First fall frostOctober 1median — 10% chance by Sep 19
Growing season140 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 29 and returns around October 11.

From the NOAA station East Hiram, ME — 10 miles away, elevation 528 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 04068

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 31 – Apr 14
SpinachSow outdoors · Mar 31 – Apr 21
Broccoli, cabbageStart indoors · Mar 3 – Mar 17
Broccoli, cabbageTransplant · Apr 21 – May 5
Onion setsPlant outdoors · Apr 14 – Apr 28
PotatoesPlant outdoors · Apr 21 – May 5
LettuceSow outdoors · Apr 14 – Apr 28
Carrots, beetsSow outdoors · Apr 21 – May 5
TomatoesStart indoors · Mar 17 – Mar 31
TomatoesTransplant · May 19 – Jun 2
Peppers, eggplantStart indoors · Mar 3 – Mar 17
Peppers, eggplantTransplant · May 26 – Jun 9
BeansSow outdoors · May 19 – Jun 2
Sweet cornSow outdoors · May 19 – Jun 2
Cucumbers, squashSow outdoors · May 19 – Jun 2
Fall lettuce, spinachSow outdoors · Aug 6 – Aug 20
GarlicPlant cloves · Sep 17 – Oct 22
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 12) and first fall frost (Oct 1) 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 04068 came on Apr 16 — 7 days earlier than the 1991–2020 average (Apr 23).

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 5a in Maine

483 plants native to the lower 48 states, recorded in Maine, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

Trees 53

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 96

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falpine bearberry0.5 ft · blooms early spring · medium shade tolerance · to −62 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °F

Wildflowers & perennials 166

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine sweetvetch2 ft · blooms early summer · high shade tolerance · to −62 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °F

Grasses 151

alpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °FAmerican beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °F

Vines 6

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °Ftrumpet honeysuckle16 ft · blooms late summer · low shade tolerance · to −33 °FVirginia creeper1 ft · blooms late spring · medium shade tolerance · to −28 °F

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 Porter, ME.

Soil in Porter, ME

The soil mapped at the center of ZIP 04068 is Lyman — moderately decomposed plant material, somewhat excessively drained.

TextureModerately decomposed plant materialtop layer
pH3.5strongly acidic; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter85%high
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Lyman-Tunbridge-Monadnock complex, 35 to 60 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 04068; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Porter, ME

Summer high79 °Faverage high, July
Winter low6 °Faverage low, January
Hot days4days a year at 90 °F or more
Freezing nights185nights a year at 32 °F or less
Growing degree days1,897base 50 °F — the season’s usable heat
Longest day15 h 28 mindaylight on June 21
Shortest day8 h 54 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation50.1 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 29 °F, low 6 °F 29°6° JanFebruary: average high 32 °F, low 7 °F 32°7° FebMarch: average high 40 °F, low 18 °F 40°18° MarApril: average high 54 °F, low 30 °F 54°30° AprMay: average high 66 °F, low 41 °F 66°41° MayJune: average high 74 °F, low 51 °F 74°51° JunJuly: average high 79 °F, low 56 °F 79°56° JulAugust: average high 78 °F, low 54 °F 78°54° AugSeptember: average high 70 °F, low 46 °F 70°46° SepOctober: average high 57 °F, low 35 °F 57°35° OctNovember: average high 45 °F, low 26 °F 45°26° NovDecember: average high 34 °F, low 15 °F 34°15° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.42 in precipitation 3.4 JanFebruary: 3.44 in precipitation 3.4 FebMarch: 4.24 in precipitation 4.2 MarApril: 4.31 in precipitation 4.3 AprMay: 3.69 in precipitation 3.7 MayJune: 4.49 in precipitation 4.5 JunJuly: 4.54 in precipitation 4.5 JulAugust: 3.75 in precipitation 3.8 AugSeptember: 3.92 in precipitation 3.9 SepOctober: 5.36 in precipitation 5.4 OctNovember: 4.36 in precipitation 4.4 NovDecember: 4.55 in precipitation 4.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: East Hiram, ME (10 mi away); precipitation: Parsonsfield 4.2 Ne, ME (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

040415a
Hiram, ME · 6 mi
038365a
Freedom, NH · 6 mi
040105a
Brownfield, ME · 7 mi
038325a
Eaton Center, NH · 7 mi
040475b
Parsonsfield, ME · 8 mi
038825a
Effingham, NH · 8 mi
040205a
Cornish, ME · 8 mi
040285a
East Parsonsfield, ME · 9 mi

Maine planting zones →

Questions about 04068

What planting zone is ZIP code 04068?

ZIP code 04068 (Porter, ME) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Porter, ME?

The median last spring frost (32 °F) near 04068 is May 12; after May 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, East Hiram station.

When is the first frost in Porter, ME?

The median first fall frost near 04068 is October 1, giving a median frost-free growing season of 140 days.

When should I plant tomatoes in 04068?

Start tomato seeds indoors around Mar 17 – Mar 31 and set transplants outside around May 19 – Jun 2, one to three weeks after the median last frost.

How much rain and snow does 04068 get?

About 50.1 inches of precipitation a year (NOAA 1991–2020 normals, Parsonsfield 4.2 Ne station).

How hot do summers get in Porter, ME?

The average high peaks at 79 °F in July, with about 4 days a year at 90 °F or more.

What kind of soil does 04068 have?

The USDA soil survey maps Lyman at the center of ZIP 04068: moderately decomposed plant material, somewhat excessively drained, pH about 3.5 (strongly acidic).

Did spring come early in Porter, ME in 2026?

Spring leaf-out near 04068 came on Apr 16 in 2026, 7 days earlier than the 1991–2020 average (Apr 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Porter, ME?

Long-day onions: the longest day near 04068 is 15 h 28 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).