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

Planting zone for 03456 — Marlow, NH

ZIP code 03456 (Marlow, Cheshire County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 15 and the first fall frost September 27.

Where ZIP 03456 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.

Zone6a−10 to −5 °F
Coldest night−23.3 to −20.6 °C
Last frostMay 15
First frostSep 27
2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Marlow, 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 Marlow, NH

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 15median — 50% chance of a later frost
Safe for tender plantsMay 29only 10% chance of frost after
First fall frostSeptember 27median — 10% chance by Sep 15
Growing season135 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 1 and returns around October 8.

From the NOAA station Bradford 2, NH — 13 miles away, elevation 814 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 03456

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 3 – Apr 17
SpinachSow outdoors · Apr 3 – Apr 24
Broccoli, cabbageStart indoors · Mar 6 – Mar 20
Broccoli, cabbageTransplant · Apr 24 – May 8
Onion setsPlant outdoors · Apr 17 – May 1
PotatoesPlant outdoors · Apr 24 – May 8
LettuceSow outdoors · Apr 17 – May 1
Carrots, beetsSow outdoors · Apr 24 – May 8
TomatoesStart indoors · Mar 20 – Apr 3
TomatoesTransplant · May 22 – Jun 5
Peppers, eggplantStart indoors · Mar 6 – Mar 20
Peppers, eggplantTransplant · May 29 – Jun 12
BeansSow outdoors · May 22 – Jun 5
Sweet cornSow outdoors · May 22 – Jun 5
Cucumbers, squashSow outdoors · May 22 – Jun 5
Fall lettuce, spinachSow outdoors · Aug 2 – Aug 16
GarlicPlant cloves · Sep 13 – Oct 18
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 15) and first fall frost (Sep 27) 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 03456 came on Apr 15 — 5 days earlier than the 1991–2020 average (Apr 20).

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 6a in New Hampshire

486 plants native to the lower 48 states, recorded in New Hampshire, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. Each links to its USDA PLANTS profile.

Trees 53

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 99

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 171

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °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 °F

Grasses 142

alpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °FAmerican beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °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 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 7

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 creeper2 ft · blooms summer · high shade tolerance · to −13 °Ftrumpet honeysuckle16 ft · blooms late summer · low shade tolerance · to −33 °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 Marlow, NH.

Soil in Marlow, NH

The soil mapped at the center of ZIP 03456 is Lyman — moderately decomposed plant material, somewhat excessively drained.

TextureModerately decomposed plant materialtop layer
pH3.5strongly acidic; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter85%high
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Lyman-Tunbridge-Rock outcrop complex, 25 to 60 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 03456; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Marlow, NH

Summer high80 °Faverage high, July
Winter low12 °Faverage low, January
Hot days3days a year at 90 °F or more
Freezing nights176nights a year at 32 °F or less
Growing degree days2,054base 50 °F — the season’s usable heat
Longest day15 h 23 mindaylight on June 21
Shortest day8 h 59 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation47.4 inper year, rain and melted snow
Snowfall80 inper year; 106 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 30 °F, low 12 °F 30°12° JanFebruary: average high 33 °F, low 13 °F 33°13° FebMarch: average high 41 °F, low 21 °F 41°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 52 °F 75°52° JunJuly: average high 80 °F, low 57 °F 80°57° JulAugust: average high 78 °F, low 55 °F 78°55° AugSeptember: average high 71 °F, low 47 °F 71°47° SepOctober: average high 58 °F, low 37 °F 58°37° OctNovember: average high 46 °F, low 28 °F 46°28° NovDecember: average high 35 °F, low 19 °F 35°19° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.37 in precipitation, 20.1 in snowfall 3.4❄20 JanFebruary: 3.23 in precipitation, 16.7 in snowfall 3.2❄17 FebMarch: 3.81 in precipitation, 17.4 in snowfall 3.8❄17 MarApril: 3.68 in precipitation, 4.6 in snowfall 3.7❄5 AprMay: 3.52 in precipitation, 0.1 in snowfall 3.5 MayJune: 4.54 in precipitation 4.5 JunJuly: 4.28 in precipitation 4.3 JulAugust: 4.32 in precipitation 4.3 AugSeptember: 3.70 in precipitation 3.7 SepOctober: 5.22 in precipitation, 0.6 in snowfall 5.2❄1 OctNovember: 3.41 in precipitation, 3 in snowfall 3.4❄3 NovDecember: 4.28 in precipitation, 17.5 in snowfall 4.3❄18 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Bradford 2, NH (13 mi away); precipitation: Marlow, NH (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

036075b
South Acworth, NH · 5 mi
034646a
Stoddard, NH · 6 mi
032806a
Washington, NH · 7 mi
036056a
Lempster, NH · 7 mi
036026a
Alstead, NH · 7 mi
034486a
Gilsum, NH · 7 mi
034456a
Sullivan, NH · 8 mi
036016a
Acworth, NH · 9 mi

New Hampshire planting zones →

Questions about 03456

What planting zone is ZIP code 03456?

ZIP code 03456 (Marlow, NH) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Marlow, NH?

The median last spring frost (32 °F) near 03456 is May 15; after May 29 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Bradford 2 station.

When is the first frost in Marlow, NH?

The median first fall frost near 03456 is September 27, giving a median frost-free growing season of 135 days.

When should I plant tomatoes in 03456?

Start tomato seeds indoors around Mar 20 – Apr 3 and set transplants outside around May 22 – Jun 5, one to three weeks after the median last frost.

How much rain and snow does 03456 get?

About 47.4 inches of precipitation a year and 80 inches of snowfall (NOAA 1991–2020 normals, Marlow station).

How hot do summers get in Marlow, NH?

The average high peaks at 80 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 03456 have?

The USDA soil survey maps Lyman at the center of ZIP 03456: moderately decomposed plant material, somewhat excessively drained, pH about 3.5 (strongly acidic).

Did spring come early in Marlow, NH in 2026?

Spring leaf-out near 03456 came on Apr 15 in 2026, 5 days earlier than the 1991–2020 average (Apr 20), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Marlow, NH?

Long-day onions: the longest day near 03456 is 15 h 23 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 03456 change?

Yes. The 2012 USDA map put 03456 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.