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

Planting zone for 59410 — Augusta, MT

ZIP code 59410 (Augusta, Lewis and Clark County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is June 12 and the first fall frost September 8.

Where ZIP 59410 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 frostJun 12
First frostSep 8
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 Augusta, 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 Augusta, MT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJune 12median — 50% chance of a later frost
Safe for tender plantsJuly 5only 10% chance of frost after
First fall frostSeptember 8median — 10% chance by Aug 23
Growing season88 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 19 and returns around September 24.

From the NOAA station Gibson Dam, MT — 9 miles away, elevation 4,590 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 59410

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · May 1 – May 15
SpinachSow outdoors · May 1 – May 22
Broccoli, cabbageStart indoors · Apr 3 – Apr 17
Broccoli, cabbageTransplant · May 22 – Jun 5
Onion setsPlant outdoors · May 15 – May 29
PotatoesPlant outdoors · May 22 – Jun 5
LettuceSow outdoors · May 15 – May 29
Carrots, beetsSow outdoors · May 22 – Jun 5
TomatoesStart indoors · Apr 17 – May 1
TomatoesTransplant · Jun 19 – Jul 3
Peppers, eggplantStart indoors · Apr 3 – Apr 17
Peppers, eggplantTransplant · Jun 26 – Jul 10
BeansSow outdoors · Jun 19 – Jul 3
Sweet cornSow outdoors · Jun 19 – Jul 3
Cucumbers, squashSow outdoors · Jun 19 – Jul 3
Fall lettuce, spinachSow outdoors · Jul 14 – Jul 28
GarlicPlant cloves · Aug 25 – Sep 29
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 12) and first fall frost (Sep 8) 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 59410 came on Apr 29 — 8 days earlier than the 1991–2020 average (May 7).

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 Augusta, MT.

Soil in Augusta, MT

The soil mapped at the center of ZIP 59410 is Regent — clay loam, well drained.

TextureClay loamholds water and nutrients; slow to drain and warm up
pH7.0neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Regent-Castner complex, 8 to 35 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 59410; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Augusta, MT

Summer high79 °Faverage high, July
Winter low12 °Faverage low, January
Hot days5days a year at 90 °F or more
Freezing nights204nights a year at 32 °F or less
Growing degree days1,018base 50 °F — the season’s usable heat
Longest day15 h 58 mindaylight on June 21
Shortest day8 h 26 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation16.6 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 36 °F, low 12 °F 36°12° JanFebruary: average high 36 °F, low 12 °F 36°12° FebMarch: average high 43 °F, low 19 °F 43°19° MarApril: average high 50 °F, low 25 °F 50°25° AprMay: average high 59 °F, low 33 °F 59°33° MayJune: average high 67 °F, low 39 °F 67°39° JunJuly: average high 79 °F, low 45 °F 79°45° JulAugust: average high 78 °F, low 43 °F 78°43° AugSeptember: average high 68 °F, low 36 °F 68°36° SepOctober: average high 54 °F, low 29 °F 54°29° OctNovember: average high 42 °F, low 20 °F 42°20° NovDecember: average high 35 °F, low 13 °F 35°13° Dec

Precipitation by month inches

0″1″2″3″4″January: 0.67 in precipitation 0.7 JanFebruary: 0.92 in precipitation 0.9 FebMarch: 0.82 in precipitation 0.8 MarApril: 1.63 in precipitation 1.6 AprMay: 2.93 in precipitation 2.9 MayJune: 3.13 in precipitation 3.1 JunJuly: 1.14 in precipitation 1.1 JulAugust: 1.33 in precipitation 1.3 AugSeptember: 1.31 in precipitation 1.3 SepOctober: 1.12 in precipitation 1.1 OctNovember: 0.78 in precipitation 0.8 NovDecember: 0.77 in precipitation 0.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Gibson Dam, MT (9 mi away); precipitation: Gibson Dam, MT (9 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.

596394b
Lincoln, MT · 22 mi
594224b
Choteau, MT · 24 mi
594364b
Fairfield, MT · 26 mi
598545a
Ovando, MT · 32 mi
594774b
Simms, MT · 32 mi
596484b
Wolf Creek, MT · 35 mi
594194b
Bynum, MT · 35 mi
594434b
Fort Shaw, MT · 38 mi

Montana planting zones →

Questions about 59410

What planting zone is ZIP code 59410?

ZIP code 59410 (Augusta, 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 Augusta, MT?

The median last spring frost (32 °F) near 59410 is June 12; after July 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Gibson Dam station.

When is the first frost in Augusta, MT?

The median first fall frost near 59410 is September 8, giving a median frost-free growing season of 88 days.

When should I plant tomatoes in 59410?

Start tomato seeds indoors around Apr 17 – May 1 and set transplants outside around Jun 19 – Jul 3, one to three weeks after the median last frost.

How much rain and snow does 59410 get?

About 16.6 inches of precipitation a year (NOAA 1991–2020 normals, Gibson Dam station).

How hot do summers get in Augusta, MT?

The average high peaks at 79 °F in July, with about 5 days a year at 90 °F or more.

What kind of soil does 59410 have?

The USDA soil survey maps Regent at the center of ZIP 59410: clay loam, well drained, pH about 7.0 (neutral).

Did spring come early in Augusta, MT in 2026?

Spring leaf-out near 59410 came on Apr 29 in 2026, 8 days earlier than the 1991–2020 average (May 7), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Augusta, MT?

Long-day onions: the longest day near 59410 is 15 h 58 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 59410 change?

Yes. The 2012 USDA map put 59410 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.