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

Planting zone for 59710 — Alder, MT

ZIP code 59710 (Alder, Madison County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is June 6 and the first fall frost September 14.

Where ZIP 59710 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.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostJun 6

First frostSep 14

2012 zone5a

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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Alder, 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 Alder, MT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 6median — 50% chance of a later frost

Safe for tender plantsJune 25only 10% chance of frost after

First fall frostSeptember 14median — 10% chance by Aug 31

Growing season98 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 16 and returns around September 26.

From the NOAA station Alder 17 S, MT — 2 miles away, elevation 5,850 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 59710

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 25 – May 9

SpinachSow outdoors · Apr 25 – May 16

Broccoli, cabbageStart indoors · Mar 28 – Apr 11

Broccoli, cabbageTransplant · May 16 – May 30

Onion setsPlant outdoors · May 9 – May 23

PotatoesPlant outdoors · May 16 – May 30

LettuceSow outdoors · May 9 – May 23

Carrots, beetsSow outdoors · May 16 – May 30

TomatoesStart indoors · Apr 11 – Apr 25

TomatoesTransplant · Jun 13 – Jun 27

Peppers, eggplantStart indoors · Mar 28 – Apr 11

Peppers, eggplantTransplant · Jun 20 – Jul 4

BeansSow outdoors · Jun 13 – Jun 27

Sweet cornSow outdoors · Jun 13 – Jun 27

Cucumbers, squashSow outdoors · Jun 13 – Jun 27

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 6) 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 59710 came on Mar 30 — 31 days earlier than the 1991–2020 average (Apr 30).

average
Apr 302026
Mar 30

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 5a in Montana

548 plants native to the lower 48 states, recorded in Montana, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

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 Alder, MT.

Soil in Alder, MT

The soil mapped at the center of ZIP 59710 is Varney — cobbly clay loam, well drained.

TextureCobbly clay loamholds water and nutrients; slow to drain and warm up

pH7.0neutral; 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: Varney cobbly clay loam, 8 to 45 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 59710; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Alder, MT

Summer high80 °Faverage high, July

Winter low14 °Faverage low, December

Hot days5days a year at 90 °F or more

Freezing nights193nights a year at 32 °F or less

Growing degree days1,366base 50 °F — the season’s usable heat

Longest day15 h 37 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)

Precipitation14.1 inper year, rain and melted snow

Snowfall57 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Alder 17 S, MT (2 mi away); precipitation: Alder 17 S, MT (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

597555a

Virginia City, MT · 16 mi

Mc Allister, MT · 34 mi

597545a

Twin Bridges, MT · 35 mi

597355a

Harrison, MT · 43 mi

Montana planting zones →

Questions about 59710

What planting zone is ZIP code 59710?

ZIP code 59710 (Alder, MT) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Alder, MT?

The median last spring frost (32 °F) near 59710 is June 6; after June 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Alder 17 S station.

When is the first frost in Alder, MT?

The median first fall frost near 59710 is September 14, giving a median frost-free growing season of 98 days.

When should I plant tomatoes in 59710?

Start tomato seeds indoors around Apr 11 – Apr 25 and set transplants outside around Jun 13 – Jun 27, one to three weeks after the median last frost.

How much rain and snow does 59710 get?

About 14.1 inches of precipitation a year and 57 inches of snowfall (NOAA 1991–2020 normals, Alder 17 S station).

How hot do summers get in Alder, MT?

The average high peaks at 80 °F in July, with about 5 days a year at 90 °F or more.

What kind of soil does 59710 have?

The USDA soil survey maps Varney at the center of ZIP 59710: cobbly clay loam, well drained, pH about 7.0 (neutral).

Did spring come early in Alder, MT in 2026?

Spring leaf-out near 59710 came on Mar 30 in 2026, 31 days earlier than the 1991–2020 average (Apr 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Alder, MT?

Long-day onions: the longest day near 59710 is 15 h 37 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).