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

Planting zone for 59257 — Redstone, MT

ZIP code 59257 (Redstone, Sheridan County) is in USDA zone 3b: the coldest winter night averages −35 to −30 °F. The median last spring frost is May 28 and the first fall frost September 7.

Where ZIP 59257 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.

Zone3b−35 to −30 °F

Coldest night−37.2 to −34.4 °C

Last frostMay 28

First frostSep 7

2012 zone3b

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 3b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Redstone, 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 Redstone, MT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 28median — 50% chance of a later frost

Safe for tender plantsJune 13only 10% chance of frost after

First fall frostSeptember 7median — 10% chance by Aug 22

Growing season101 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 18 and returns around September 16.

From the NOAA station Redstone, MT — 4 miles away, elevation 2,106 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 59257

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 16 – Apr 30

SpinachSow outdoors · Apr 16 – May 7

Broccoli, cabbageStart indoors · Mar 19 – Apr 2

Broccoli, cabbageTransplant · May 7 – May 21

Onion setsPlant outdoors · Apr 30 – May 14

PotatoesPlant outdoors · May 7 – May 21

LettuceSow outdoors · Apr 30 – May 14

Carrots, beetsSow outdoors · May 7 – May 21

TomatoesStart indoors · Apr 2 – Apr 16

TomatoesTransplant · Jun 4 – Jun 18

Peppers, eggplantStart indoors · Mar 19 – Apr 2

Peppers, eggplantTransplant · Jun 11 – Jun 25

BeansSow outdoors · Jun 4 – Jun 18

Sweet cornSow outdoors · Jun 4 – Jun 18

Cucumbers, squashSow outdoors · Jun 4 – Jun 18

Fall lettuce, spinachSow outdoors · Jul 13 – Jul 27

GarlicPlant cloves · Aug 24 – Sep 28

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 28) and first fall frost (Sep 7) 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 59257 came on Apr 21 — about the same time as the 1991–2020 average (Apr 22).

average
Apr 222026
Apr 21

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 3b in Montana

304 plants native to the lower 48 states, recorded in Montana, and rated by the USDA to survive −35 °F or colder — the bottom of zone 3b. 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 Redstone, MT.

Soil in Redstone, MT

The soil mapped at the center of ZIP 59257 is Lambert — silty clay loam, well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up

pH7.9alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Lambert-Zahill complex, 20 to 50 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 59257; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Redstone, MT

Summer high82 °Faverage high, July

Winter low−1 °Faverage low, January

Hot days23days a year at 90 °F or more

Freezing nights209nights a year at 32 °F or less

Growing degree days1,725base 50 °F — the season’s usable heat

Longest day16 h 10 mindaylight on June 21

Shortest day8 h 16 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation14.3 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: Redstone, MT (4 mi away); precipitation: Redstone, MT (4 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.

592224a

Flaxville, MT · 11 mi

592543b

Plentywood, MT · 14 mi

Whitetail, MT · 19 mi

592564a

Raymond, MT · 21 mi

592473b

Medicine Lake, MT · 25 mi

592113b

Antelope, MT · 27 mi

Montana planting zones →

Questions about 59257

What planting zone is ZIP code 59257?

ZIP code 59257 (Redstone, MT) is in USDA hardiness zone 3b on the 2023 map: the coldest night of an average winter reaches −35 to −30 °F (−37.2 to −34.4 °C).

When is the last frost in Redstone, MT?

The median last spring frost (32 °F) near 59257 is May 28; after June 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Redstone station.

When is the first frost in Redstone, MT?

The median first fall frost near 59257 is September 7, giving a median frost-free growing season of 101 days.

When should I plant tomatoes in 59257?

Start tomato seeds indoors around Apr 2 – Apr 16 and set transplants outside around Jun 4 – Jun 18, one to three weeks after the median last frost.

How much rain and snow does 59257 get?

About 14.3 inches of precipitation a year (NOAA 1991–2020 normals, Redstone station).

How hot do summers get in Redstone, MT?

The average high peaks at 82 °F in July, with about 23 days a year at 90 °F or more.

What kind of soil does 59257 have?

The USDA soil survey maps Lambert at the center of ZIP 59257: silty clay loam, well drained, pH about 7.9 (alkaline).

Did spring come early in Redstone, MT in 2026?

Spring leaf-out near 59257 came on Apr 21 in 2026, about the same as the 1991–2020 average (Apr 22), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Redstone, MT?

Long-day onions: the longest day near 59257 is 16 h 10 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).