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

Planting zone for 59751 — Silver Star, MT

ZIP code 59751 (Silver Star, Madison County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is June 8 and the first fall frost September 2.

Where ZIP 59751 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 frostJun 8
First frostSep 2
2012 zone5a

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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Silver Star, 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 Silver Star, MT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJune 8median — 50% chance of a later frost
Safe for tender plantsJuly 1only 10% chance of frost after
First fall frostSeptember 2median — 10% chance by Aug 16
Growing season82 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 20 and returns around September 15.

From the NOAA station Twin Bridges, MT — 10 miles away, elevation 4,626 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 59751

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 27 – May 11
SpinachSow outdoors · Apr 27 – May 18
Broccoli, cabbageStart indoors · Mar 30 – Apr 13
Broccoli, cabbageTransplant · May 18 – Jun 1
Onion setsPlant outdoors · May 11 – May 25
PotatoesPlant outdoors · May 18 – Jun 1
LettuceSow outdoors · May 11 – May 25
Carrots, beetsSow outdoors · May 18 – Jun 1
TomatoesStart indoors · Apr 13 – Apr 27
TomatoesTransplant · Jun 15 – Jun 29
Peppers, eggplantStart indoors · Mar 30 – Apr 13
Peppers, eggplantTransplant · Jun 22 – Jul 6
BeansSow outdoors · Jun 15 – Jun 29
Sweet cornSow outdoors · Jun 15 – Jun 29
Cucumbers, squashSow outdoors · Jun 15 – Jun 29
Fall lettuce, spinachSow outdoors · Jul 8 – Jul 22
GarlicPlant cloves · Aug 19 – Sep 23
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 8) and first fall frost (Sep 2) 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 59751 came on Mar 20 — 28 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 5a in Montana

548 plants native to the lower 48 states, recorded in Montana, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

Trees 26

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 96

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °Falderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °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 °F

Wildflowers & perennials 253

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

Grasses 161

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 Silver Star, MT.

Soil in Silver Star, MT

The soil mapped at the center of ZIP 59751 is Trimad — cobbly loam, well drained.

TextureCobbly loama good balance for most vegetables
pH7.2neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Trimad cobbly loam, 15 to 45 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 59751; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Silver Star, MT

Summer high85 °Faverage high, July
Winter low12 °Faverage low, December
Hot days17days a year at 90 °F or more
Freezing nights206nights a year at 32 °F or less
Growing degree days1,505base 50 °F — the season’s usable heat
Longest day15 h 43 mindaylight on June 21
Shortest day8 h 41 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation9.4 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 35 °F, low 13 °F 35°13° JanFebruary: average high 40 °F, low 15 °F 40°15° FebMarch: average high 49 °F, low 22 °F 49°22° MarApril: average high 57 °F, low 28 °F 57°28° AprMay: average high 66 °F, low 36 °F 66°36° MayJune: average high 75 °F, low 43 °F 75°43° JunJuly: average high 85 °F, low 46 °F 85°46° JulAugust: average high 83 °F, low 43 °F 83°43° AugSeptember: average high 74 °F, low 37 °F 74°37° SepOctober: average high 59 °F, low 28 °F 59°28° OctNovember: average high 44 °F, low 19 °F 44°19° NovDecember: average high 35 °F, low 12 °F 35°12° Dec

Precipitation by month inches

0″1″2″3″January: 0.22 in precipitation 0.2 JanFebruary: 0.22 in precipitation 0.2 FebMarch: 0.37 in precipitation 0.4 MarApril: 0.85 in precipitation 0.8 AprMay: 1.70 in precipitation 1.7 MayJune: 2.17 in precipitation 2.2 JunJuly: 0.89 in precipitation 0.9 JulAugust: 0.75 in precipitation 0.8 AugSeptember: 0.88 in precipitation 0.9 SepOctober: 0.73 in precipitation 0.7 OctNovember: 0.33 in precipitation 0.3 NovDecember: 0.33 in precipitation 0.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Twin Bridges, MT (10 mi away); precipitation: Twin Bridges, MT (10 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.

597545a
Twin Bridges, MT · 12 mi
597595a
Whitehall, MT · 12 mi
597475a
Pony, MT · 16 mi
597495a
Sheridan, MT · 20 mi
597355a
Harrison, MT · 22 mi
597024a
Butte, MT · 22 mi
597034a
Butte, MT · 22 mi
597324b
Glen, MT · 23 mi

Montana planting zones →

Questions about 59751

What planting zone is ZIP code 59751?

ZIP code 59751 (Silver Star, MT) 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 Silver Star, MT?

The median last spring frost (32 °F) near 59751 is June 8; after July 1 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Twin Bridges station.

When is the first frost in Silver Star, MT?

The median first fall frost near 59751 is September 2, giving a median frost-free growing season of 82 days.

When should I plant tomatoes in 59751?

Start tomato seeds indoors around Apr 13 – Apr 27 and set transplants outside around Jun 15 – Jun 29, one to three weeks after the median last frost.

How much rain and snow does 59751 get?

About 9.4 inches of precipitation a year (NOAA 1991–2020 normals, Twin Bridges station).

How hot do summers get in Silver Star, MT?

The average high peaks at 85 °F in July, with about 17 days a year at 90 °F or more.

What kind of soil does 59751 have?

The USDA soil survey maps Trimad at the center of ZIP 59751: cobbly loam, well drained, pH about 7.2 (neutral).

Did spring come early in Silver Star, MT in 2026?

Spring leaf-out near 59751 came on Mar 20 in 2026, 28 days earlier than the 1991–2020 average (Apr 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Silver Star, MT?

Long-day onions: the longest day near 59751 is 15 h 43 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).