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

Planting zone for 59447 — Geyser, MT

ZIP code 59447 (Geyser, Judith Basin County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 22 and the first fall frost September 23.

Where ZIP 59447 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 frostMay 22
First frostSep 23
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 Geyser, 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 Geyser, MT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 22median — 50% chance of a later frost
Safe for tender plantsJune 9only 10% chance of frost after
First fall frostSeptember 23median — 10% chance by Sep 7
Growing season123 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 7 and returns around October 2.

From the NOAA station Raynesford 2 Nnw, MT — 14 miles away, elevation 4,216 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 59447

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 10 – Apr 24
SpinachSow outdoors · Apr 10 – May 1
Broccoli, cabbageStart indoors · Mar 13 – Mar 27
Broccoli, cabbageTransplant · May 1 – May 15
Onion setsPlant outdoors · Apr 24 – May 8
PotatoesPlant outdoors · May 1 – May 15
LettuceSow outdoors · Apr 24 – May 8
Carrots, beetsSow outdoors · May 1 – May 15
TomatoesStart indoors · Mar 27 – Apr 10
TomatoesTransplant · May 29 – Jun 12
Peppers, eggplantStart indoors · Mar 13 – Mar 27
Peppers, eggplantTransplant · Jun 5 – Jun 19
BeansSow outdoors · May 29 – Jun 12
Sweet cornSow outdoors · May 29 – Jun 12
Cucumbers, squashSow outdoors · May 29 – Jun 12
Fall lettuce, spinachSow outdoors · Jul 29 – Aug 12
GarlicPlant cloves · Sep 9 – Oct 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 22) and first fall frost (Sep 23) 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 59447 came on Mar 12 — 31 days earlier than the 1991–2020 average (Apr 12).

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 4b in Montana

506 plants native to the lower 48 states, recorded in Montana, and rated by the USDA to survive −25 °F or colder — the bottom of zone 4b. Each links to its USDA PLANTS profile.

Trees 23

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 87

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 229

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 155

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 Geyser, MT.

Soil in Geyser, MT

The soil mapped at the center of ZIP 59447 is Judith — gravelly clay loam, well drained.

TextureGravelly 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 matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Judith gravelly clay loam, low terrace, 0 to 4 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 59447; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Geyser, MT

Summer high83 °Faverage high, August
Winter low17 °Faverage low, January
Hot days14days a year at 90 °F or more
Freezing nights165nights a year at 32 °F or less
Growing degree days1,804base 50 °F — the season’s usable heat
Longest day15 h 56 mindaylight on June 21
Shortest day8 h 28 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation21.6 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 37 °F, low 17 °F 37°17° JanFebruary: average high 38 °F, low 17 °F 38°17° FebMarch: average high 46 °F, low 23 °F 46°23° MarApril: average high 55 °F, low 31 °F 55°31° AprMay: average high 64 °F, low 39 °F 64°39° MayJune: average high 71 °F, low 46 °F 71°46° JunJuly: average high 82 °F, low 52 °F 82°52° JulAugust: average high 83 °F, low 51 °F 83°51° AugSeptember: average high 72 °F, low 43 °F 72°43° SepOctober: average high 57 °F, low 34 °F 57°34° OctNovember: average high 44 °F, low 25 °F 44°25° NovDecember: average high 37 °F, low 18 °F 37°18° Dec

Precipitation by month inches

0″1″2″3″4″January: 1.05 in precipitation 1.1 JanFebruary: 0.88 in precipitation 0.9 FebMarch: 1.27 in precipitation 1.3 MarApril: 2.51 in precipitation 2.5 AprMay: 2.88 in precipitation 2.9 MayJune: 3.68 in precipitation 3.7 JunJuly: 1.75 in precipitation 1.8 JulAugust: 1.51 in precipitation 1.5 AugSeptember: 2.09 in precipitation 2.1 SepOctober: 1.69 in precipitation 1.7 OctNovember: 1.24 in precipitation 1.2 NovDecember: 1.05 in precipitation 1.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Raynesford 2 Nnw, MT (14 mi away); precipitation: Raynesford 2 Nnw, MT (14 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4b.

594694b
Raynesford, MT · 13 mi
594244b
Coffee Creek, MT · 17 mi
594794b
Stanford, MT · 19 mi
594124b
Belt, MT · 19 mi
594504b
Highwood, MT · 23 mi
594634b
Monarch, MT · 26 mi
594654b
Neihart, MT · 27 mi
594464b
Geraldine, MT · 29 mi

Montana planting zones →

Questions about 59447

What planting zone is ZIP code 59447?

ZIP code 59447 (Geyser, 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 Geyser, MT?

The median last spring frost (32 °F) near 59447 is May 22; after June 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Raynesford 2 Nnw station.

When is the first frost in Geyser, MT?

The median first fall frost near 59447 is September 23, giving a median frost-free growing season of 123 days.

When should I plant tomatoes in 59447?

Start tomato seeds indoors around Mar 27 – Apr 10 and set transplants outside around May 29 – Jun 12, one to three weeks after the median last frost.

How much rain and snow does 59447 get?

About 21.6 inches of precipitation a year (NOAA 1991–2020 normals, Raynesford 2 Nnw station).

How hot do summers get in Geyser, MT?

The average high peaks at 83 °F in August, with about 14 days a year at 90 °F or more.

What kind of soil does 59447 have?

The USDA soil survey maps Judith at the center of ZIP 59447: gravelly clay loam, well drained, pH about 7.9 (alkaline).

Did spring come early in Geyser, MT in 2026?

Spring leaf-out near 59447 came on Mar 12 in 2026, 31 days earlier than the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Geyser, MT?

Long-day onions: the longest day near 59447 is 15 h 56 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 59447 change?

Yes. The 2012 USDA map put 59447 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.