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

Planting zone for 04786 — Washburn, ME

ZIP code 04786 (Washburn, Aroostook County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 7 and the first fall frost October 1.

Where ZIP 04786 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 frostMay 7

First frostOct 1

2012 zone4a

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 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Washburn, 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 Washburn, ME

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 7median — 50% chance of a later frost

Safe for tender plantsMay 24only 10% chance of frost after

First fall frostOctober 1median — 10% chance by Sep 17

Growing season143 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 26 and returns around October 12.

From the NOAA station Caribou Municipal Airport, ME — 10 miles away, elevation 623 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 04786

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 26 – Apr 9

SpinachSow outdoors · Mar 26 – Apr 16

Broccoli, cabbageStart indoors · Feb 26 – Mar 12

Broccoli, cabbageTransplant · Apr 16 – Apr 30

Onion setsPlant outdoors · Apr 9 – Apr 23

PotatoesPlant outdoors · Apr 16 – Apr 30

LettuceSow outdoors · Apr 9 – Apr 23

Carrots, beetsSow outdoors · Apr 16 – Apr 30

TomatoesStart indoors · Mar 12 – Mar 26

TomatoesTransplant · May 14 – May 28

Peppers, eggplantStart indoors · Feb 26 – Mar 12

Peppers, eggplantTransplant · May 21 – Jun 4

BeansSow outdoors · May 14 – May 28

Sweet cornSow outdoors · May 14 – May 28

Cucumbers, squashSow outdoors · May 14 – May 28

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 7) 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 04786 came on May 1 — about the same time as the 1991–2020 average (May 3).

average
May 32026
May 1

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).

Soil in Washburn, ME

The soil mapped at the center of ZIP 04786 is Perham — moderately decomposed plant material, moderately well drained.

TextureModerately decomposed plant materialtop layer

pH4.0strongly acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter53%high

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Perham gravelly silt loam, 2 to 8 percent slopes.

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 04786; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Washburn, ME

Summer high77 °Faverage high, July

Winter low3 °Faverage low, January

Hot days2days a year at 90 °F or more

Freezing nights180nights a year at 32 °F or less

Growing degree days1,726base 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)

Precipitation40.7 inper year, rain and melted snow

Snowfall118 inper year; 136 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: Caribou Municipal Airport, ME (10 mi away); precipitation: Caribou Municipal Airport, ME (10 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4a.

047384a

Crouseville, ME · 5 mi

Presque Isle, ME · 12 mi

047624a

New Sweden, ME · 13 mi

Fort Fairfield, ME · 16 mi

Maine planting zones →

Questions about 04786

What planting zone is ZIP code 04786?

ZIP code 04786 (Washburn, 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 Washburn, ME?

The median last spring frost (32 °F) near 04786 is May 7; after May 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Caribou Municipal Airport station.

When is the first frost in Washburn, ME?

The median first fall frost near 04786 is October 1, giving a median frost-free growing season of 143 days.

When should I plant tomatoes in 04786?

Start tomato seeds indoors around Mar 12 – Mar 26 and set transplants outside around May 14 – May 28, one to three weeks after the median last frost.

How much rain and snow does 04786 get?

About 40.7 inches of precipitation a year and 118 inches of snowfall (NOAA 1991–2020 normals, Caribou Municipal Airport station).

How hot do summers get in Washburn, 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 04786 have?

The USDA soil survey maps Perham at the center of ZIP 04786: moderately decomposed plant material, moderately well drained, pH about 4.0 (strongly acidic).

Did spring come early in Washburn, ME in 2026?

Spring leaf-out near 04786 came on May 1 in 2026, about the same as the 1991–2020 average (May 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Washburn, ME?

Long-day onions: the longest day near 04786 is 15 h 52 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).