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

Planting zone for 03588 — Milan, NH

ZIP code 03588 (Milan, Coos County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 30 and the first fall frost September 19.

Where ZIP 03588 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.

Zone4b−25 to −20 °F

Coldest night−31.7 to −28.9 °C

Last frostMay 30

First frostSep 19

2012 zone4a

Was 4a 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 4b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Milan, NH…

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 Milan, NH

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 30median — 50% chance of a later frost

Safe for tender plantsJune 11only 10% chance of frost after

First fall frostSeptember 19median — 10% chance by Sep 5

Growing season112 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 17 and returns around September 30.

From the NOAA station Berlin Municipal Airport, NH — 4 miles away, elevation 1,158 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 03588

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 18 – May 2

SpinachSow outdoors · Apr 18 – May 9

Broccoli, cabbageStart indoors · Mar 21 – Apr 4

Broccoli, cabbageTransplant · May 9 – May 23

Onion setsPlant outdoors · May 2 – May 16

PotatoesPlant outdoors · May 9 – May 23

LettuceSow outdoors · May 2 – May 16

Carrots, beetsSow outdoors · May 9 – May 23

TomatoesStart indoors · Apr 4 – Apr 18

TomatoesTransplant · Jun 6 – Jun 20

Peppers, eggplantStart indoors · Mar 21 – Apr 4

Peppers, eggplantTransplant · Jun 13 – Jun 27

BeansSow outdoors · Jun 6 – Jun 20

Sweet cornSow outdoors · Jun 6 – Jun 20

Cucumbers, squashSow outdoors · Jun 6 – Jun 20

Fall lettuce, spinachSow outdoors · Jul 25 – Aug 8

GarlicPlant cloves · Sep 5 – Oct 10

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 30) and first fall frost (Sep 19) 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 03588 came on Apr 18 — 10 days earlier than the 1991–2020 average (Apr 28).

average
Apr 282026
Apr 18

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 4b in New Hampshire

438 plants native to the lower 48 states, recorded in New Hampshire, and rated by the USDA to survive −25 °F or colder — the bottom of zone 4b. 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 Milan, NH.

Soil in Milan, NH

The soil mapped at the center of ZIP 03588 is Marlow — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH3.5strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter85%high

Hydrologic groupCwater soaks in slowly

Farmland classFarmland of local importanceUSDA classification

Map unit: Marlow fine sandy loam, 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 03588; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Milan, NH

Summer high80 °Faverage high, July

Winter low3 °Faverage low, January

Hot days4days a year at 90 °F or more

Freezing nights197nights a year at 32 °F or less

Growing degree days1,679base 50 °F — the season’s usable heat

Longest day15 h 34 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)

Precipitation36.5 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: Berlin Municipal Airport, NH (4 mi away); precipitation: Berlin Municipal Airport, NH (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

4 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

035704b

Berlin, NH · 7 mi

035894a

Mount Washington, NH · 10 mi

035824b

Groveton, NH · 11 mi

035974a

West Stewartstown, NH · 12 mi

042615a

Newry, ME · 14 mi

035834b

Jefferson, NH · 18 mi

New Hampshire planting zones →

Questions about 03588

What planting zone is ZIP code 03588?

ZIP code 03588 (Milan, NH) is in USDA hardiness zone 4b on the 2023 map: the coldest night of an average winter reaches −25 to −20 °F (−31.7 to −28.9 °C).

When is the last frost in Milan, NH?

The median last spring frost (32 °F) near 03588 is May 30; after June 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Berlin Municipal Airport station.

When is the first frost in Milan, NH?

The median first fall frost near 03588 is September 19, giving a median frost-free growing season of 112 days.

When should I plant tomatoes in 03588?

Start tomato seeds indoors around Apr 4 – Apr 18 and set transplants outside around Jun 6 – Jun 20, one to three weeks after the median last frost.

How much rain and snow does 03588 get?

About 36.5 inches of precipitation a year (NOAA 1991–2020 normals, Berlin Municipal Airport station).

How hot do summers get in Milan, NH?

The average high peaks at 80 °F in July, with about 4 days a year at 90 °F or more.

What kind of soil does 03588 have?

The USDA soil survey maps Marlow at the center of ZIP 03588: slightly decomposed plant material, well drained, pH about 3.5 (strongly acidic).

Did spring come early in Milan, NH in 2026?

Spring leaf-out near 03588 came on Apr 18 in 2026, 10 days earlier than the 1991–2020 average (Apr 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Milan, NH?

Long-day onions: the longest day near 03588 is 15 h 34 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 03588 change?

Yes. The 2012 USDA map put 03588 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.