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

Planting zone for 04490 — Topsfield, ME

ZIP code 04490 (Topsfield, Washington County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 6 and the first fall frost October 8.

Where ZIP 04490 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.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostMay 6

First frostOct 8

2012 zone4b

Was 4b 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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Topsfield, 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 Topsfield, 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 18only 10% chance of frost after

First fall frostOctober 8median — 10% chance by Sep 28

Growing season155 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 25 and returns around October 21.

From the NOAA station Topsfield 2, ME — 6 miles away, elevation 620 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 04490

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 13 – Aug 27

GarlicPlant cloves · Sep 24 – Oct 29

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 6) and first fall frost (Oct 8) 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 04490 came on Apr 27 — about the same time as the 1991–2020 average (Apr 28).

average
Apr 282026
Apr 27

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 Topsfield, ME

The soil mapped at the center of ZIP 04490 is Telos — moderately decomposed plant material, somewhat poorly drained.

TextureModerately decomposed plant materialtop layer

DrainageSomewhat poorly drainedconsider raised beds

Organic matter53%high

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Telos-Monarda-Monson association, 0 to 8 percent slopes, 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 04490; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Topsfield, ME

Summer high78 °Faverage high, July

Winter low7 °Faverage low, January

Hot days2days a year at 90 °F or more

Freezing nights170nights a year at 32 °F or less

Growing degree days1,878base 50 °F — the season’s usable heat

Longest day15 h 40 mindaylight on June 21

Shortest day8 h 43 mindaylight on December 21

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

Precipitation52.1 inper year, rain and melted snow

Snowfall115 inper year; 127 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: Topsfield 2, ME (6 mi away); precipitation: Topsfield 2, ME (6 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.

Springfield, ME · 13 mi

046375b

Grand Lake Stream, ME · 15 mi

046685b

Princeton, ME · 15 mi

044545a

Lambert Lake, ME · 17 mi

044915a

Vanceboro, ME · 19 mi

044244b

Danforth, ME · 19 mi

Maine planting zones →

Questions about 04490

What planting zone is ZIP code 04490?

ZIP code 04490 (Topsfield, ME) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Topsfield, ME?

The median last spring frost (32 °F) near 04490 is May 6; after May 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Topsfield 2 station.

When is the first frost in Topsfield, ME?

The median first fall frost near 04490 is October 8, giving a median frost-free growing season of 155 days.

When should I plant tomatoes in 04490?

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 04490 get?

About 52.1 inches of precipitation a year and 115 inches of snowfall (NOAA 1991–2020 normals, Topsfield 2 station).

How hot do summers get in Topsfield, ME?

The average high peaks at 78 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 04490 have?

The USDA soil survey maps Telos at the center of ZIP 04490: moderately decomposed plant material, somewhat poorly drained.

Did spring come early in Topsfield, ME in 2026?

Spring leaf-out near 04490 came on Apr 27 in 2026, about the same as the 1991–2020 average (Apr 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Topsfield, ME?

Long-day onions: the longest day near 04490 is 15 h 40 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 04490 change?

Yes. The 2012 USDA map put 04490 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.