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

Planting zone for 04746 — Grand Isle, ME

ZIP code 04746 (Grand Isle, Aroostook County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 6 and the first fall frost October 2.

Where ZIP 04746 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 6

First frostOct 2

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 Grand Isle, 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 Grand Isle, ME

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 6median — 50% chance of a later frost

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

First fall frostOctober 2median — 10% chance by Sep 18

Growing season147 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 27 and returns around October 17.

From the NOAA station Frenchville Aroostook Airport, ME — 8 miles away, elevation 988 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 04746

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 25 – Apr 8

SpinachSow outdoors · Mar 25 – Apr 15

Broccoli, cabbageStart indoors · Feb 25 – Mar 11

Broccoli, cabbageTransplant · Apr 15 – Apr 29

Onion setsPlant outdoors · Apr 8 – Apr 22

PotatoesPlant outdoors · Apr 15 – Apr 29

LettuceSow outdoors · Apr 8 – Apr 22

Carrots, beetsSow outdoors · Apr 15 – Apr 29

TomatoesStart indoors · Mar 11 – Mar 25

TomatoesTransplant · May 13 – May 27

Peppers, eggplantStart indoors · Feb 25 – Mar 11

Peppers, eggplantTransplant · May 20 – Jun 3

BeansSow outdoors · May 13 – May 27

Sweet cornSow outdoors · May 13 – May 27

Cucumbers, squashSow outdoors · May 13 – May 27

Fall lettuce, spinachSow outdoors · Aug 7 – Aug 21

GarlicPlant cloves · Sep 18 – Oct 23

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 6) and first fall frost (Oct 2) 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 04746 came on May 5 — about the same time as the 1991–2020 average (May 5).

average
May 52026
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 Grand Isle, ME.

Soil in Grand Isle, ME

The soil mapped at the center of ZIP 04746 is Plaisted — highly decomposed plant material, well drained.

TextureHighly decomposed plant materialtop layer

DrainageWell drainednatural drainage class

Organic matter53%high

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Plaisted-Howland association, 8 to 15 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 04746; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Grand Isle, ME

Summer high76 °Faverage high, July

Winter low3 °Faverage low, January

Hot days1days a year at 90 °F or more

Freezing nights183nights a year at 32 °F or less

Growing degree days1,663base 50 °F — the season’s usable heat

Longest day15 h 56 mindaylight on June 21

Shortest day8 h 28 mindaylight on December 21

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

Precipitation32.9 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Frenchville Aroostook Airport, ME (8 mi away); precipitation: Frenchville Aroostook Airport, ME (8 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.

047734b

Saint David, ME · 4 mi

047724a

Saint Agatha, ME · 8 mi

047564b

Madawaska, ME · 9 mi

047854a

Van Buren, ME · 10 mi

047454b

Frenchville, ME · 12 mi

047794a

Sinclair, ME · 12 mi

047834a

Stockholm, ME · 15 mi

047624a

New Sweden, ME · 19 mi

Maine planting zones →

Questions about 04746

What planting zone is ZIP code 04746?

ZIP code 04746 (Grand Isle, 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 Grand Isle, ME?

The median last spring frost (32 °F) near 04746 is May 6; after May 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Frenchville Aroostook Airport station.

When is the first frost in Grand Isle, ME?

The median first fall frost near 04746 is October 2, giving a median frost-free growing season of 147 days.

When should I plant tomatoes in 04746?

Start tomato seeds indoors around Mar 11 – Mar 25 and set transplants outside around May 13 – May 27, one to three weeks after the median last frost.

How much rain and snow does 04746 get?

About 32.9 inches of precipitation a year (NOAA 1991–2020 normals, Frenchville Aroostook Airport station).

How hot do summers get in Grand Isle, ME?

The average high peaks at 76 °F in July, with about 1 days a year at 90 °F or more.

What kind of soil does 04746 have?

The USDA soil survey maps Plaisted at the center of ZIP 04746: highly decomposed plant material, well drained.

Did spring come early in Grand Isle, ME in 2026?

Spring leaf-out near 04746 came on May 5 in 2026, about the same as the 1991–2020 average (May 5), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Grand Isle, ME?

Long-day onions: the longest day near 04746 is 15 h 56 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 04746 change?

Yes. The 2012 USDA map put 04746 in zone 3b; the 2023 map puts it in zone 4a. The newer map uses 1991–2020 data and more weather stations.