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

Planting zone for 04579 — Woolwich, ME

ZIP code 04579 (Woolwich, Sagadahoc County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 8 and the first fall frost October 7.

Where ZIP 04579 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.

Zone5b−15 to −10 °F
Coldest night−26.1 to −23.3 °C
Last frostMay 8
First frostOct 7
2012 zone5b

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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Woolwich, 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 Woolwich, ME

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 8median — 50% chance of a later frost
Safe for tender plantsMay 20only 10% chance of frost after
First fall frostOctober 7median — 10% chance by Sep 24
Growing season151 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 26 and returns around October 21.

From the NOAA station Wiscasset Airport, ME — 3 miles away, elevation 69 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 04579

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 27 – Apr 10
SpinachSow outdoors · Mar 27 – Apr 17
Broccoli, cabbageStart indoors · Feb 27 – Mar 13
Broccoli, cabbageTransplant · Apr 17 – May 1
Onion setsPlant outdoors · Apr 10 – Apr 24
PotatoesPlant outdoors · Apr 17 – May 1
LettuceSow outdoors · Apr 10 – Apr 24
Carrots, beetsSow outdoors · Apr 17 – May 1
TomatoesStart indoors · Mar 13 – Mar 27
TomatoesTransplant · May 15 – May 29
Peppers, eggplantStart indoors · Feb 27 – Mar 13
Peppers, eggplantTransplant · May 22 – Jun 5
BeansSow outdoors · May 15 – May 29
Sweet cornSow outdoors · May 15 – May 29
Cucumbers, squashSow outdoors · May 15 – May 29
Fall lettuce, spinachSow outdoors · Aug 12 – Aug 26
GarlicPlant cloves · Sep 23 – Oct 28
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 8) and first fall frost (Oct 7) 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 04579 came on Apr 16 — 5 days earlier than the 1991–2020 average (Apr 21).

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 5b in Maine

493 plants native to the lower 48 states, recorded in Maine, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. Each links to its USDA PLANTS profile.

Trees 55

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 98

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 169

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 153

alpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °FAmerican beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °FAmerican cupscale3 ft · blooms early summer · high shade tolerance · to −18 °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 °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 Woolwich, ME.

Soil in Woolwich, ME

The soil mapped at the center of ZIP 04579 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-Abram complex, 15 to 35 percent slopes, very rocky.

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 04579; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Woolwich, ME

Summer high79 °Faverage high, July
Winter low12 °Faverage low, January
Hot days3days a year at 90 °F or more
Freezing nights160nights a year at 32 °F or less
Growing degree days2,067base 50 °F — the season’s usable heat
Longest day15 h 29 mindaylight on June 21
Shortest day8 h 53 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation46.7 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 32 °F, low 12 °F 32°12° JanFebruary: average high 35 °F, low 14 °F 35°14° FebMarch: average high 43 °F, low 23 °F 43°23° MarApril: average high 54 °F, low 33 °F 54°33° AprMay: average high 65 °F, low 42 °F 65°42° MayJune: average high 74 °F, low 52 °F 74°52° JunJuly: average high 79 °F, low 58 °F 79°58° JulAugust: average high 79 °F, low 57 °F 79°57° AugSeptember: average high 71 °F, low 49 °F 71°49° SepOctober: average high 59 °F, low 38 °F 59°38° OctNovember: average high 48 °F, low 29 °F 48°29° NovDecember: average high 38 °F, low 20 °F 38°20° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.51 in precipitation 3.5 JanFebruary: 3.08 in precipitation 3.1 FebMarch: 3.77 in precipitation 3.8 MarApril: 3.94 in precipitation 3.9 AprMay: 3.46 in precipitation 3.5 MayJune: 4.47 in precipitation 4.5 JunJuly: 3.44 in precipitation 3.4 JulAugust: 3.08 in precipitation 3.1 AugSeptember: 4.15 in precipitation 4.2 SepOctober: 5.13 in precipitation 5.1 OctNovember: 4.45 in precipitation 4.5 NovDecember: 4.22 in precipitation 4.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Wiscasset Airport, ME (3 mi away); precipitation: Wiscasset Airport, ME (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

045785b
Wiscasset, ME · 4 mi
045306a
Bath, ME · 6 mi
045716a
Trevett, ME · 6 mi
040085b
Bowdoinham, ME · 7 mi
045565b
Edgecomb, ME · 8 mi
045376a
Boothbay, ME · 8 mi
045486a
Georgetown, ME · 9 mi
043425b
Dresden, ME · 9 mi

Maine planting zones →

Questions about 04579

What planting zone is ZIP code 04579?

ZIP code 04579 (Woolwich, ME) is in USDA hardiness zone 5b on the 2023 map: the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C).

When is the last frost in Woolwich, ME?

The median last spring frost (32 °F) near 04579 is May 8; after May 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Wiscasset Airport station.

When is the first frost in Woolwich, ME?

The median first fall frost near 04579 is October 7, giving a median frost-free growing season of 151 days.

When should I plant tomatoes in 04579?

Start tomato seeds indoors around Mar 13 – Mar 27 and set transplants outside around May 15 – May 29, one to three weeks after the median last frost.

How much rain and snow does 04579 get?

About 46.7 inches of precipitation a year (NOAA 1991–2020 normals, Wiscasset Airport station).

How hot do summers get in Woolwich, ME?

The average high peaks at 79 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 04579 have?

The USDA soil survey maps Lyman at the center of ZIP 04579: moderately decomposed plant material, somewhat excessively drained, pH about 3.5 (strongly acidic).

Did spring come early in Woolwich, ME in 2026?

Spring leaf-out near 04579 came on Apr 16 in 2026, 5 days earlier than the 1991–2020 average (Apr 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Woolwich, ME?

Long-day onions: the longest day near 04579 is 15 h 29 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).