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

Planting zone for 59071 — Roscoe, MT

ZIP code 59071 (Roscoe, Carbon County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is June 5 and the first fall frost September 14.

Where ZIP 59071 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 5

First frostSep 14

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 Roscoe, 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 Roscoe, MT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 5median — 50% chance of a later frost

Safe for tender plantsJune 21only 10% chance of frost after

First fall frostSeptember 14median — 10% chance by Aug 31

Growing season99 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 24 and returns around September 25.

From the NOAA station Mystic Lake, MT — 5 miles away, elevation 6,546 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 59071

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 24 – May 8

SpinachSow outdoors · Apr 24 – May 15

Broccoli, cabbageStart indoors · Mar 27 – Apr 10

Broccoli, cabbageTransplant · May 15 – May 29

Onion setsPlant outdoors · May 8 – May 22

PotatoesPlant outdoors · May 15 – May 29

LettuceSow outdoors · May 8 – May 22

Carrots, beetsSow outdoors · May 15 – May 29

TomatoesStart indoors · Apr 10 – Apr 24

TomatoesTransplant · Jun 12 – Jun 26

Peppers, eggplantStart indoors · Mar 27 – Apr 10

Peppers, eggplantTransplant · Jun 19 – Jul 3

BeansSow outdoors · Jun 12 – Jun 26

Sweet cornSow outdoors · Jun 12 – Jun 26

Cucumbers, squashSow outdoors · Jun 12 – Jun 26

Fall lettuce, spinachSow outdoors · Jul 20 – Aug 3

GarlicPlant cloves · Aug 31 – Oct 5

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 5) and first fall frost (Sep 14) 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 59071 came on May 3 — 8 days earlier than the 1991–2020 average (May 11).

average
May 112026
May 3

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.

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 Roscoe, MT.

Soil in Roscoe, MT

The center of ZIP 59071 is mapped as No Digital Data Available: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 59071; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Roscoe, MT

Summer high75 °Faverage high, July

Winter low17 °Faverage low, February

Hot days0days a year at 90 °F or more

Freezing nights178nights a year at 32 °F or less

Growing degree days1,215base 50 °F — the season’s usable heat

Longest day15 h 39 mindaylight on June 21

Shortest day8 h 44 mindaylight on December 21

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

Precipitation26.5 inper year, rain and melted snow

Snowfall193 inper year; 128 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mystic Lake, MT (5 mi away); precipitation: Mystic Lake, MT (5 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.

590285a

Fishtail, MT · 6 mi

590685a

Red Lodge, MT · 12 mi

590615a

Nye, MT · 17 mi

590015a

Absarokee, MT · 20 mi

590075a

Bearcreek, MT · 22 mi

590705a

Roberts, MT · 23 mi

590814a

Silver Gate, MT · 23 mi

590204b

Cooke City, MT · 25 mi

Montana planting zones →

Questions about 59071

What planting zone is ZIP code 59071?

ZIP code 59071 (Roscoe, 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 Roscoe, MT?

The median last spring frost (32 °F) near 59071 is June 5; after June 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mystic Lake station.

When is the first frost in Roscoe, MT?

The median first fall frost near 59071 is September 14, giving a median frost-free growing season of 99 days.

When should I plant tomatoes in 59071?

Start tomato seeds indoors around Apr 10 – Apr 24 and set transplants outside around Jun 12 – Jun 26, one to three weeks after the median last frost.

How much rain and snow does 59071 get?

About 26.5 inches of precipitation a year and 193 inches of snowfall (NOAA 1991–2020 normals, Mystic Lake station).

How hot do summers get in Roscoe, MT?

The average high peaks at 75 °F in July, with about 0 days a year at 90 °F or more.

Did spring come early in Roscoe, MT in 2026?

Spring leaf-out near 59071 came on May 3 in 2026, 8 days earlier than the 1991–2020 average (May 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Roscoe, MT?

Long-day onions: the longest day near 59071 is 15 h 39 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).