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

Planting zone for 59020 — Cooke City, MT

ZIP code 59020 (Cooke City, Park County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is June 5 and the first fall frost September 14.

Where ZIP 59020 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.

Zone4b−25 to −20 °F
Coldest night−31.7 to −28.9 °C
Last frostJun 5
First frostSep 14
2012 zone4a

Was 4a 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 4b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Cooke City, 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 Cooke City, 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 — 20 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 59020

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 59020 came on May 14 — 4 days earlier than the 1991–2020 average (May 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).

Soil in Cooke City, MT

The center of ZIP 59020 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 59020; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cooke City, MT

Summer high74 °Faverage high, July
Winter low6 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights272nights a year at 32 °F or less
Growing degree days463base 50 °F — the season’s usable heat
Longest day15 h 38 mindaylight on June 21
Shortest day8 h 45 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation25.6 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°32 °FJanuary: average high 24 °F, low 6 °F 24°6° JanFebruary: average high 29 °F, low 7 °F 29°7° FebMarch: average high 37 °F, low 14 °F 37°14° MarApril: average high 43 °F, low 21 °F 43°21° AprMay: average high 54 °F, low 28 °F 54°28° MayJune: average high 64 °F, low 35 °F 64°35° JunJuly: average high 74 °F, low 39 °F 74°39° JulAugust: average high 71 °F, low 38 °F 71°38° AugSeptember: average high 62 °F, low 31 °F 62°31° SepOctober: average high 47 °F, low 24 °F 47°24° OctNovember: average high 31 °F, low 13 °F 31°13° NovDecember: average high 22 °F, low 6 °F 22°6° Dec

Precipitation by month inches

0″1″2″3″January: 2.25 in precipitation 2.3 JanFebruary: 1.93 in precipitation 1.9 FebMarch: 1.93 in precipitation 1.9 MarApril: 2.26 in precipitation 2.3 AprMay: 2.71 in precipitation 2.7 MayJune: 2.83 in precipitation 2.8 JunJuly: 1.73 in precipitation 1.7 JulAugust: 1.47 in precipitation 1.5 AugSeptember: 1.75 in precipitation 1.8 SepOctober: 2.24 in precipitation 2.2 OctNovember: 2.23 in precipitation 2.2 NovDecember: 2.26 in precipitation 2.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Cooke City 2 W, MT (9 mi away); precipitation: Northeast Entrance, MT (8 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

590814a
Silver Gate, MT · 8 mi
590285a
Fishtail, MT · 23 mi
590304b
Gardiner, MT · 24 mi
590525a
Mc Leod, MT · 25 mi
590715a
Roscoe, MT · 25 mi
590615a
Nye, MT · 25 mi
590685a
Red Lodge, MT · 26 mi
590655a
Pray, MT · 30 mi

Montana planting zones →

Questions about 59020

What planting zone is ZIP code 59020?

ZIP code 59020 (Cooke City, MT) is in USDA hardiness zone 4b on the 2023 map: the coldest night of an average winter reaches −25 to −20 °F (−31.7 to −28.9 °C).

When is the last frost in Cooke City, MT?

The median last spring frost (32 °F) near 59020 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 Cooke City, MT?

The median first fall frost near 59020 is September 14, giving a median frost-free growing season of 99 days.

When should I plant tomatoes in 59020?

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 59020 get?

About 25.6 inches of precipitation a year (NOAA 1991–2020 normals, Northeast Entrance station).

How hot do summers get in Cooke City, MT?

The average high peaks at 74 °F in July, with about 0 days a year at 90 °F or more.

Did spring come early in Cooke City, MT in 2026?

Spring leaf-out near 59020 came on May 14 in 2026, 4 days earlier than the 1991–2020 average (May 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cooke City, MT?

Long-day onions: the longest day near 59020 is 15 h 38 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 59020 change?

Yes. The 2012 USDA map put 59020 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.