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

Planting zone for 59248 — Nashua, MT

ZIP code 59248 (Nashua, Valley County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 12 and the first fall frost September 24.

Where ZIP 59248 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.

Zone4a−30 to −25 °F
Coldest night−34.4 to −31.7 °C
Last frostMay 12
First frostSep 24
2012 zone4a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Nashua, MT…

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 Nashua, MT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 12median — 50% chance of a later frost
Safe for tender plantsMay 26only 10% chance of frost after
First fall frostSeptember 24median — 10% chance by Sep 12
Growing season134 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 1 and returns around October 2.

From the NOAA station Nashua #2, MT — 9 miles away, elevation 2,067 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 59248

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 31 – Apr 14
SpinachSow outdoors · Mar 31 – Apr 21
Broccoli, cabbageStart indoors · Mar 3 – Mar 17
Broccoli, cabbageTransplant · Apr 21 – May 5
Onion setsPlant outdoors · Apr 14 – Apr 28
PotatoesPlant outdoors · Apr 21 – May 5
LettuceSow outdoors · Apr 14 – Apr 28
Carrots, beetsSow outdoors · Apr 21 – May 5
TomatoesStart indoors · Mar 17 – Mar 31
TomatoesTransplant · May 19 – Jun 2
Peppers, eggplantStart indoors · Mar 3 – Mar 17
Peppers, eggplantTransplant · May 26 – Jun 9
BeansSow outdoors · May 19 – Jun 2
Sweet cornSow outdoors · May 19 – Jun 2
Cucumbers, squashSow outdoors · May 19 – Jun 2
Fall lettuce, spinachSow outdoors · Jul 30 – Aug 13
GarlicPlant cloves · Sep 10 – Oct 15
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 12) and first fall frost (Sep 24) 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 59248 came on Apr 20 — about the same time as the 1991–2020 average (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 4a in Montana

439 plants native to the lower 48 states, recorded in Montana, and rated by the USDA to survive −30 °F or colder — the bottom of zone 4a. Each links to its USDA PLANTS profile.

Trees 21

American elm120 ft · blooms early spring · medium shade tolerance · to −46 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fboxelder60 ft · blooms early spring · low shade tolerance · to −46 °FDouglas-fir200 ft · blooms mid spring · medium shade tolerance · to −33 °Feastern cottonwood190 ft · blooms spring · high shade tolerance · to −43 °F

Shrubs 77

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °Falderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FBarclay's willow15 ft · high shade tolerance · to −43 °F

Wildflowers & perennials 189

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 bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °F

Grasses 141

Alaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °Falkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °FAlpine Meadow-Foxtail0.5 ft · blooms mid spring · medium shade tolerance · to −33 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °Fanalogue sedge1.5 ft · blooms late spring · medium shade tolerance · to −38 °F

Vines 3

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fwestern white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °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 Nashua, MT.

Soil in Nashua, MT

The soil mapped at the center of ZIP 59248 is Scobey — clay loam, well drained.

TextureClay loamholds water and nutrients; slow to drain and warm up
pH6.8neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Scobey-Kevin clay loams, 2 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 59248; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Nashua, MT

Summer high88 °Faverage high, July
Winter low3 °Faverage low, January
Hot days40days a year at 90 °F or more
Freezing nights183nights a year at 32 °F or less
Growing degree days2,510base 50 °F — the season’s usable heat
Longest day16 h 05 mindaylight on June 21
Shortest day8 h 20 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation13.7 inper year, rain and melted snow

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 26 °F, low 3 °F 26°3° JanFebruary: average high 31 °F, low 8 °F 31°8° FebMarch: average high 45 °F, low 19 °F 45°19° MarApril: average high 61 °F, low 32 °F 61°32° AprMay: average high 71 °F, low 42 °F 71°42° MayJune: average high 79 °F, low 52 °F 79°52° JunJuly: average high 88 °F, low 57 °F 88°57° JulAugust: average high 88 °F, low 56 °F 88°56° AugSeptember: average high 76 °F, low 45 °F 76°45° SepOctober: average high 59 °F, low 32 °F 59°32° OctNovember: average high 42 °F, low 18 °F 42°18° NovDecember: average high 29 °F, low 7 °F 29°7° Dec

Precipitation by month inches

0″1″2″3″January: 0.37 in precipitation 0.4 JanFebruary: 0.34 in precipitation 0.3 FebMarch: 0.51 in precipitation 0.5 MarApril: 1.12 in precipitation 1.1 AprMay: 2.32 in precipitation 2.3 MayJune: 2.87 in precipitation 2.9 JunJuly: 1.93 in precipitation 1.9 JulAugust: 1.31 in precipitation 1.3 AugSeptember: 1.18 in precipitation 1.2 SepOctober: 0.94 in precipitation 0.9 OctNovember: 0.45 in precipitation 0.5 NovDecember: 0.39 in precipitation 0.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Nashua #2, MT (9 mi away); precipitation: Glasgow 10.1 Se, MT (16 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

592254a
Frazer, MT · 13 mi
592314a
Saint Marie, MT · 17 mi
592234a
Fort Peck, MT · 23 mi
592443b
Larslan, MT · 26 mi
592304a
Glasgow, MT · 26 mi
592014a
Wolf Point, MT · 30 mi
592734a
Vandalia, MT · 32 mi
592533b
Peerless, MT · 38 mi

Montana planting zones →

Questions about 59248

What planting zone is ZIP code 59248?

ZIP code 59248 (Nashua, MT) is in USDA hardiness zone 4a on the 2023 map: the coldest night of an average winter reaches −30 to −25 °F (−34.4 to −31.7 °C).

When is the last frost in Nashua, MT?

The median last spring frost (32 °F) near 59248 is May 12; after May 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Nashua #2 station.

When is the first frost in Nashua, MT?

The median first fall frost near 59248 is September 24, giving a median frost-free growing season of 134 days.

When should I plant tomatoes in 59248?

Start tomato seeds indoors around Mar 17 – Mar 31 and set transplants outside around May 19 – Jun 2, one to three weeks after the median last frost.

How much rain and snow does 59248 get?

About 13.7 inches of precipitation a year (NOAA 1991–2020 normals, Glasgow 10.1 Se station).

How hot do summers get in Nashua, MT?

The average high peaks at 88 °F in July, with about 40 days a year at 90 °F or more.

What kind of soil does 59248 have?

The USDA soil survey maps Scobey at the center of ZIP 59248: clay loam, well drained, pH about 6.8 (neutral).

Did spring come early in Nashua, MT in 2026?

Spring leaf-out near 59248 came on Apr 20 in 2026, about the same as the 1991–2020 average (Apr 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Nashua, MT?

Long-day onions: the longest day near 59248 is 16 h 05 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).