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

Planting zone for 03070 — New Boston, NH

ZIP code 03070 (New Boston, Hillsborough) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 2 and the first fall frost October 8.

Where ZIP 03070 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 2
First frostOct 8
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 New Boston, 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 New Boston, NH

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 8median — 10% chance by Sep 27
Growing season158 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 21 and returns around October 20.

From the NOAA station Weare, NH — 8 miles away, elevation 722 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 03070

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 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 2) 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 03070 came on Apr 12 — 5 days earlier than the 1991–2020 average (Apr 17).

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 New Boston, NH.

Soil in New Boston, NH

The soil mapped at the center of ZIP 03070 is Windsor — moderately decomposed plant material, excessively drained.

TextureModerately decomposed plant materialtop layer
DrainageExcessively drainednatural drainage class
Organic matter95%high
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Windsor loamy sand, 15 to 35 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 03070; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in New Boston, NH

Summer high80 °Faverage high, July
Winter low13 °Faverage low, January
Hot days4days a year at 90 °F or more
Freezing nights166nights a year at 32 °F or less
Growing degree days2,251base 50 °F — the season’s usable heat
Longest day15 h 22 mindaylight on June 21
Shortest day9 h 00 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

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 31 °F, low 13 °F 31°13° JanFebruary: average high 34 °F, low 14 °F 34°14° FebMarch: average high 42 °F, low 23 °F 42°23° MarApril: average high 55 °F, low 33 °F 55°33° AprMay: average high 67 °F, low 45 °F 67°45° MayJune: average high 75 °F, low 55 °F 75°55° JunJuly: average high 80 °F, low 60 °F 80°60° JulAugust: average high 78 °F, low 58 °F 78°58° AugSeptember: average high 71 °F, low 50 °F 71°50° SepOctober: average high 58 °F, low 38 °F 58°38° OctNovember: average high 47 °F, low 30 °F 47°30° NovDecember: average high 37 °F, low 20 °F 37°20° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.26 in precipitation 3.3 JanFebruary: 3.17 in precipitation 3.2 FebMarch: 3.78 in precipitation 3.8 MarApril: 3.67 in precipitation 3.7 AprMay: 3.61 in precipitation 3.6 MayJune: 4.50 in precipitation 4.5 JunJuly: 4.42 in precipitation 4.4 JulAugust: 4.07 in precipitation 4.1 AugSeptember: 3.74 in precipitation 3.7 SepOctober: 4.92 in precipitation 4.9 OctNovember: 3.88 in precipitation 3.9 NovDecember: 4.39 in precipitation 4.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Weare, NH (8 mi away); precipitation: Weare 2 Ne, NH (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

030576a
Mont Vernon, NH · 5 mi
030436a
Francestown, NH · 7 mi
030826a
Lyndeborough, NH · 7 mi
030456a
Goffstown, NH · 7 mi
032816a
Weare, NH · 7 mi
031106a
Bedford, NH · 8 mi
030316a
Amherst, NH · 8 mi
030476a
Greenfield, NH · 10 mi

New Hampshire planting zones →

Questions about 03070

What planting zone is ZIP code 03070?

ZIP code 03070 (New Boston, 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 New Boston, NH?

The median last spring frost (32 °F) near 03070 is May 2; after May 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Weare station.

When is the first frost in New Boston, NH?

The median first fall frost near 03070 is October 8, giving a median frost-free growing season of 158 days.

When should I plant tomatoes in 03070?

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 03070 get?

About 47.4 inches of precipitation a year (NOAA 1991–2020 normals, Weare 2 Ne station).

How hot do summers get in New Boston, 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 03070 have?

The USDA soil survey maps Windsor at the center of ZIP 03070: moderately decomposed plant material, excessively drained.

Did spring come early in New Boston, NH in 2026?

Spring leaf-out near 03070 came on Apr 12 in 2026, 5 days earlier than the 1991–2020 average (Apr 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in New Boston, NH?

Long-day onions: the longest day near 03070 is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 03070 change?

Yes. The 2012 USDA map put 03070 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.