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

Planting zone for 04736 — Caribou, ME

ZIP code 04736 (Caribou, 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 04736 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 zone4b

Was 4b on the 2012 map — half a zone colder 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 Caribou, 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 Caribou, 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 — 3 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 04736

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 04736 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).

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 Caribou, ME.

Soil in Caribou, ME

The soil mapped at the center of ZIP 04736 is Caribou — gravelly loam, well drained.

TextureGravelly loama good balance for most vegetables

pH5.1strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter5.5%high

Hydrologic groupBwater soaks in moderately

Farmland classprime farmlandUSDA classification

Map unit: Caribou gravelly 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 04736; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Caribou, 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 53 mindaylight on June 21

Shortest day8 h 31 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 (3 mi away); precipitation: Caribou Municipal Airport, ME (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4a.

047624a

New Sweden, ME · 6 mi

Crouseville, ME · 11 mi

047834a

Stockholm, ME · 11 mi

047424a

Fort Fairfield, ME · 12 mi

047854a

Van Buren, ME · 14 mi

Maine planting zones →

Questions about 04736

What planting zone is ZIP code 04736?

ZIP code 04736 (Caribou, 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 Caribou, ME?

The median last spring frost (32 °F) near 04736 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 Caribou, ME?

The median first fall frost near 04736 is October 1, giving a median frost-free growing season of 143 days.

When should I plant tomatoes in 04736?

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 04736 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 Caribou, 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 04736 have?

The USDA soil survey maps Caribou at the center of ZIP 04736: gravelly loam, well drained, pH about 5.1 (strongly acidic).

Did spring come early in Caribou, ME in 2026?

Spring leaf-out near 04736 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 Caribou, ME?

Long-day onions: the longest day near 04736 is 15 h 53 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 04736 change?

Yes. The 2012 USDA map put 04736 in zone 4b; the 2023 map puts it in zone 4a. The newer map uses 1991–2020 data and more weather stations.