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

Planting zone for 59259 — Richey, MT

ZIP code 59259 (Richey, Dawson County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 16 and the first fall frost September 22.

Where ZIP 59259 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 16

First frostSep 22

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 Richey, 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 Richey, MT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 16median — 50% chance of a later frost

Safe for tender plantsMay 31only 10% chance of frost after

First fall frostSeptember 22median — 10% chance by Sep 10

Growing season129 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 4 and returns around October 1.

From the NOAA station Vida 6 Ne, MT — 19 miles away, elevation 2,284 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 59259

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 4 – Apr 18

SpinachSow outdoors · Apr 4 – Apr 25

Broccoli, cabbageStart indoors · Mar 7 – Mar 21

Broccoli, cabbageTransplant · Apr 25 – May 9

Onion setsPlant outdoors · Apr 18 – May 2

PotatoesPlant outdoors · Apr 25 – May 9

LettuceSow outdoors · Apr 18 – May 2

Carrots, beetsSow outdoors · Apr 25 – May 9

TomatoesStart indoors · Mar 21 – Apr 4

TomatoesTransplant · May 23 – Jun 6

Peppers, eggplantStart indoors · Mar 7 – Mar 21

Peppers, eggplantTransplant · May 30 – Jun 13

BeansSow outdoors · May 23 – Jun 6

Sweet cornSow outdoors · May 23 – Jun 6

Cucumbers, squashSow outdoors · May 23 – Jun 6

Fall lettuce, spinachSow outdoors · Jul 28 – Aug 11

GarlicPlant cloves · Sep 8 – Oct 13

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 16) and first fall frost (Sep 22) 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 59259 came on Apr 8 — 9 days earlier than the 1991–2020 average (Apr 17).

average
Apr 172026
Apr 8

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 Richey, MT

The soil mapped at the center of ZIP 59259 is Cherry — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH7.9alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2.5%moderate

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Cherry-Cambert-Cabba silt loams, 4 to 15 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 59259; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Richey, MT

Summer high85 °Faverage high, July

Winter low5 °Faverage low, January

Hot days25days a year at 90 °F or more

Freezing nights183nights a year at 32 °F or less

Growing degree days2,232base 50 °F — the season’s usable heat

Longest day16 h 00 mindaylight on June 21

Shortest day8 h 25 mindaylight on December 21

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

Precipitation16.7 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Vida 6 Ne, MT (19 mi away); precipitation: Brockton 20s, MT (16 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.

592744a

Vida, MT · 19 mi

593154a

Bloomfield, MT · 19 mi

Montana planting zones →

Questions about 59259

What planting zone is ZIP code 59259?

ZIP code 59259 (Richey, 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 Richey, MT?

The median last spring frost (32 °F) near 59259 is May 16; after May 31 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Vida 6 Ne station.

When is the first frost in Richey, MT?

The median first fall frost near 59259 is September 22, giving a median frost-free growing season of 129 days.

When should I plant tomatoes in 59259?

Start tomato seeds indoors around Mar 21 – Apr 4 and set transplants outside around May 23 – Jun 6, one to three weeks after the median last frost.

How much rain and snow does 59259 get?

About 16.7 inches of precipitation a year (NOAA 1991–2020 normals, Brockton 20s station).

How hot do summers get in Richey, MT?

The average high peaks at 85 °F in July, with about 25 days a year at 90 °F or more.

What kind of soil does 59259 have?

The USDA soil survey maps Cherry at the center of ZIP 59259: silt loam, well drained, pH about 7.9 (alkaline).

Did spring come early in Richey, MT in 2026?

Spring leaf-out near 59259 came on Apr 8 in 2026, 9 days earlier than the 1991–2020 average (Apr 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Richey, MT?

Long-day onions: the longest day near 59259 is 16 h 00 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).