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

Planting zone for 04903 — Waterville, ME

ZIP code 04903 (Waterville, Kennebec County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 2 and the first fall frost October 10.

Where ZIP 04903 is

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 2
First frostOct 10
2012 zone5a

Was 5a 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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Waterville, 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 Waterville, ME

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 2median — 50% chance of a later frost
Safe for tender plantsMay 14only 10% chance of frost after
First fall frostOctober 10median — 10% chance by Sep 30
Growing season159 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 22 and returns around October 24.

From the NOAA station Waterville Trtmt Plt, ME — 3 miles away, elevation 72 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 04903

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 21 – Apr 4
SpinachSow outdoors · Mar 21 – Apr 11
Broccoli, cabbageStart indoors · Feb 21 – Mar 7
Broccoli, cabbageTransplant · Apr 11 – Apr 25
Onion setsPlant outdoors · Apr 4 – Apr 18
PotatoesPlant outdoors · Apr 11 – Apr 25
LettuceSow outdoors · Apr 4 – Apr 18
Carrots, beetsSow outdoors · Apr 11 – Apr 25
TomatoesStart indoors · Mar 7 – Mar 21
TomatoesTransplant · May 9 – May 23
Peppers, eggplantStart indoors · Feb 21 – Mar 7
Peppers, eggplantTransplant · May 16 – May 30
BeansSow outdoors · May 9 – May 23
Sweet cornSow outdoors · May 9 – May 23
Cucumbers, squashSow outdoors · May 9 – May 23
Fall lettuce, spinachSow outdoors · Aug 15 – Aug 29
GarlicPlant cloves · Sep 26 – Oct 31
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 2) and first fall frost (Oct 10) 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 04903 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 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 Waterville, ME.

Soil in Waterville, ME

The soil mapped at the center of ZIP 04903 is Peru — fine sandy loam, moderately well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter7%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classprime farmlandUSDA classification

Map unit: Peru fine sandy loam, 3 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 04903; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Waterville, ME

Summer high80 °Faverage high, July
Winter low9 °Faverage low, January
Hot days6days a year at 90 °F or more
Freezing nights164nights a year at 32 °F or less
Growing degree days2,201base 50 °F — the season’s usable heat
Longest day15 h 33 mindaylight on June 21
Shortest day8 h 49 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation43.4 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 9 °F 29°9° JanFebruary: average high 32 °F, low 10 °F 32°10° FebMarch: average high 40 °F, low 21 °F 40°21° MarApril: average high 54 °F, low 32 °F 54°32° AprMay: average high 66 °F, low 43 °F 66°43° MayJune: average high 75 °F, low 53 °F 75°53° JunJuly: average high 80 °F, low 59 °F 80°59° JulAugust: average high 80 °F, low 57 °F 80°57° AugSeptember: average high 72 °F, low 50 °F 72°50° SepOctober: average high 59 °F, low 38 °F 59°38° OctNovember: average high 46 °F, low 29 °F 46°29° NovDecember: average high 35 °F, low 17 °F 35°17° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.12 in precipitation 3.1 JanFebruary: 2.61 in precipitation 2.6 FebMarch: 3.27 in precipitation 3.3 MarApril: 3.73 in precipitation 3.7 AprMay: 3.33 in precipitation 3.3 MayJune: 4.03 in precipitation 4.0 JunJuly: 3.37 in precipitation 3.4 JulAugust: 3.39 in precipitation 3.4 AugSeptember: 3.82 in precipitation 3.8 SepOctober: 4.90 in precipitation 4.9 OctNovember: 3.87 in precipitation 3.9 NovDecember: 3.92 in precipitation 3.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Waterville Trtmt Plt, ME (3 mi away); precipitation: Waterville Trtmt Plt, ME (3 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.

049625b
North Vassalboro, ME · 6 mi
049015b
Waterville, ME · 7 mi
049175b
Belgrade, ME · 7 mi
049375a
Fairfield, ME · 8 mi
049185a
Belgrade Lakes, ME · 8 mi
049785a
Smithfield, ME · 8 mi
049755b
Shawmut, ME · 8 mi
049355b
East Vassalboro, ME · 9 mi

All 2 ZIP codes in Waterville → · Maine planting zones →

Questions about 04903

What planting zone is ZIP code 04903?

ZIP code 04903 (Waterville, 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 Waterville, ME?

The median last spring frost (32 °F) near 04903 is May 2; after May 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Waterville Trtmt Plt station.

When is the first frost in Waterville, ME?

The median first fall frost near 04903 is October 10, giving a median frost-free growing season of 159 days.

When should I plant tomatoes in 04903?

Start tomato seeds indoors around Mar 7 – Mar 21 and set transplants outside around May 9 – May 23, one to three weeks after the median last frost.

How much rain and snow does 04903 get?

About 43.4 inches of precipitation a year (NOAA 1991–2020 normals, Waterville Trtmt Plt station).

How hot do summers get in Waterville, ME?

The average high peaks at 80 °F in July, with about 6 days a year at 90 °F or more.

What kind of soil does 04903 have?

The USDA soil survey maps Peru at the center of ZIP 04903: fine sandy loam, moderately well drained, pH about 5.0 (strongly acidic).

Did spring come early in Waterville, ME in 2026?

Spring leaf-out near 04903 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 Waterville, ME?

Long-day onions: the longest day near 04903 is 15 h 33 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 04903 change?

Yes. The 2012 USDA map put 04903 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.