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

Planting zone for 59435 — Ethridge, MT

ZIP code 59435 (Ethridge, Toole County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 23 and the first fall frost September 16.

Where ZIP 59435 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.

Zone4a−30 to −25 °F
Coldest night−34.4 to −31.7 °C
Last frostMay 23
First frostSep 16
2012 zone4a

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 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Ethridge, 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 Ethridge, MT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 23median — 50% chance of a later frost
Safe for tender plantsJune 6only 10% chance of frost after
First fall frostSeptember 16median — 10% chance by Sep 3
Growing season115 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 10 and returns around September 26.

From the NOAA station Shelby, MT — 9 miles away, elevation 3,327 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 59435

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 11 – Apr 25
SpinachSow outdoors · Apr 11 – May 2
Broccoli, cabbageStart indoors · Mar 14 – Mar 28
Broccoli, cabbageTransplant · May 2 – May 16
Onion setsPlant outdoors · Apr 25 – May 9
PotatoesPlant outdoors · May 2 – May 16
LettuceSow outdoors · Apr 25 – May 9
Carrots, beetsSow outdoors · May 2 – May 16
TomatoesStart indoors · Mar 28 – Apr 11
TomatoesTransplant · May 30 – Jun 13
Peppers, eggplantStart indoors · Mar 14 – Mar 28
Peppers, eggplantTransplant · Jun 6 – Jun 20
BeansSow outdoors · May 30 – Jun 13
Sweet cornSow outdoors · May 30 – Jun 13
Cucumbers, squashSow outdoors · May 30 – Jun 13
Fall lettuce, spinachSow outdoors · Jul 22 – Aug 5
GarlicPlant cloves · Sep 2 – Oct 7
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 23) and first fall frost (Sep 16) 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 59435 came on Mar 23 — 26 days earlier than the 1991–2020 average (Apr 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 Ethridge, MT

The soil mapped at the center of ZIP 59435 is Joplin — loam, well drained.

TextureLoama good balance for most vegetables
pH7.1neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupCwater soaks in slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Joplin-Hillon loams, 2 to 8 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 59435; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Ethridge, MT

Summer high82 °Faverage high, July
Winter low6 °Faverage low, January
Hot days18days a year at 90 °F or more
Freezing nights190nights a year at 32 °F or less
Growing degree days1,697base 50 °F — the season’s usable heat
Longest day16 h 08 mindaylight on June 21
Shortest day8 h 17 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation12.6 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 31 °F, low 6 °F 31°6° JanFebruary: average high 35 °F, low 10 °F 35°10° FebMarch: average high 44 °F, low 18 °F 44°18° MarApril: average high 54 °F, low 28 °F 54°28° AprMay: average high 64 °F, low 38 °F 64°38° MayJune: average high 73 °F, low 46 °F 73°46° JunJuly: average high 82 °F, low 52 °F 82°52° JulAugust: average high 82 °F, low 49 °F 82°49° AugSeptember: average high 71 °F, low 41 °F 71°41° SepOctober: average high 56 °F, low 29 °F 56°29° OctNovember: average high 42 °F, low 18 °F 42°18° NovDecember: average high 33 °F, low 9 °F 33°9° Dec

Precipitation by month inches

0″1″2″3″4″January: 0.32 in precipitation 0.3 JanFebruary: 0.33 in precipitation 0.3 FebMarch: 0.48 in precipitation 0.5 MarApril: 1.23 in precipitation 1.2 AprMay: 1.94 in precipitation 1.9 MayJune: 3.03 in precipitation 3.0 JunJuly: 1.30 in precipitation 1.3 JulAugust: 1.18 in precipitation 1.2 AugSeptember: 1.23 in precipitation 1.2 SepOctober: 0.68 in precipitation 0.7 OctNovember: 0.53 in precipitation 0.5 NovDecember: 0.30 in precipitation 0.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Shelby, MT (9 mi away); precipitation: Ethridge, MT (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

594544a
Kevin, MT · 13 mi
594664a
Oilmont, MT · 16 mi
594744a
Shelby, MT · 16 mi
594824a
Sunburst, MT · 22 mi
594864b
Valier, MT · 23 mi
594254a
Conrad, MT · 28 mi
594274a
Cut Bank, MT · 31 mi
594844a
Sweet Grass, MT · 35 mi

Montana planting zones →

Questions about 59435

What planting zone is ZIP code 59435?

ZIP code 59435 (Ethridge, MT) is in USDA hardiness zone 4a on the 2023 map: the coldest night of an average winter reaches −30 to −25 °F (−34.4 to −31.7 °C).

When is the last frost in Ethridge, MT?

The median last spring frost (32 °F) near 59435 is May 23; after June 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Shelby station.

When is the first frost in Ethridge, MT?

The median first fall frost near 59435 is September 16, giving a median frost-free growing season of 115 days.

When should I plant tomatoes in 59435?

Start tomato seeds indoors around Mar 28 – Apr 11 and set transplants outside around May 30 – Jun 13, one to three weeks after the median last frost.

How much rain and snow does 59435 get?

About 12.6 inches of precipitation a year (NOAA 1991–2020 normals, Ethridge station).

How hot do summers get in Ethridge, MT?

The average high peaks at 82 °F in July, with about 18 days a year at 90 °F or more.

What kind of soil does 59435 have?

The USDA soil survey maps Joplin at the center of ZIP 59435: loam, well drained, pH about 7.1 (neutral).

Did spring come early in Ethridge, MT in 2026?

Spring leaf-out near 59435 came on Mar 23 in 2026, 26 days earlier than the 1991–2020 average (Apr 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Ethridge, MT?

Long-day onions: the longest day near 59435 is 16 h 08 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).