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

Planting zone for 59412 — Belt, MT

ZIP code 59412 (Belt, Cascade 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 59412 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 Belt, 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 Belt, 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 — 6 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 59412

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 59412 came on Mar 5 — 38 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).

Soil in Belt, MT

The soil mapped at the center of ZIP 59412 is Bitton — stony loam, well drained.

TextureStony 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: Bitton and Roy soils, 10 to 65 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 59412; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Belt, 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 (6 mi away); precipitation: Raynesford 2 Nnw, MT (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4b.

594694b
Raynesford, MT · 11 mi
594804b
Stockett, MT · 12 mi
594724b
Sand Coulee, MT · 16 mi
594634b
Monarch, MT · 18 mi
594504b
Highwood, MT · 18 mi
594474b
Geyser, MT · 19 mi
594054b
Great Falls, MT · 20 mi
594014b
Great Falls, MT · 24 mi

Montana planting zones →

Questions about 59412

What planting zone is ZIP code 59412?

ZIP code 59412 (Belt, 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 Belt, MT?

The median last spring frost (32 °F) near 59412 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 Belt, MT?

The median first fall frost near 59412 is September 23, giving a median frost-free growing season of 123 days.

When should I plant tomatoes in 59412?

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 59412 get?

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

How hot do summers get in Belt, 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 59412 have?

The USDA soil survey maps Bitton at the center of ZIP 59412: stony loam, well drained, pH about 7.2 (neutral).

Did spring come early in Belt, MT in 2026?

Spring leaf-out near 59412 came on Mar 5 in 2026, 38 days earlier than the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Belt, MT?

Long-day onions: the longest day near 59412 is 15 h 56 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 59412 change?

Yes. The 2012 USDA map put 59412 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.