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

Planting zone for 59868 — Seeley Lake, MT

ZIP code 59868 (Seeley Lake, Missoula County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 20 and the first fall frost September 22.

Where ZIP 59868 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 frostMay 20
First frostSep 22
2012 zone4a

Was 4a on the 2012 map — a full zone warmer now. 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 Seeley Lake, 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 Seeley Lake, MT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 20median — 50% chance of a later frost
Safe for tender plantsJune 7only 10% chance of frost after
First fall frostSeptember 22median — 10% chance by Sep 5
Growing season120 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 3 and returns around October 4.

From the NOAA station Lindbergh Lake, MT — 16 miles away, elevation 4,321 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 59868

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 8 – Apr 22
SpinachSow outdoors · Apr 8 – Apr 29
Broccoli, cabbageStart indoors · Mar 11 – Mar 25
Broccoli, cabbageTransplant · Apr 29 – May 13
Onion setsPlant outdoors · Apr 22 – May 6
PotatoesPlant outdoors · Apr 29 – May 13
LettuceSow outdoors · Apr 22 – May 6
Carrots, beetsSow outdoors · Apr 29 – May 13
TomatoesStart indoors · Mar 25 – Apr 8
TomatoesTransplant · May 27 – Jun 10
Peppers, eggplantStart indoors · Mar 11 – Mar 25
Peppers, eggplantTransplant · Jun 3 – Jun 17
BeansSow outdoors · May 27 – Jun 10
Sweet cornSow outdoors · May 27 – Jun 10
Cucumbers, squashSow outdoors · May 27 – Jun 10
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 20) 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 59868 came on Apr 18 — 8 days earlier than the 1991–2020 average (Apr 26).

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.

Trees 26

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 96

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 253

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 161

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 Seeley Lake, MT.

Soil in Seeley Lake, MT

The soil mapped at the center of ZIP 59868 is Glaciercreek — slightly decomposed plant material, excessively drained.

TextureSlightly decomposed plant materialtop layer
pH6.5neutral; most vegetables like 6.0–7.0
DrainageExcessively drainednatural drainage class
Organic matter50%high
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Glaciercreek gravelly silt loam, 0 to 4 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 59868; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Seeley Lake, MT

Summer high83 °Faverage high, July
Winter low12 °Faverage low, January
Hot days15days a year at 90 °F or more
Freezing nights215nights a year at 32 °F or less
Growing degree days1,308base 50 °F — the season’s usable heat
Longest day15 h 56 mindaylight on June 21
Shortest day8 h 29 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
Snowfall119 inper year; 141 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 32 °F, low 12 °F 32°12° JanFebruary: average high 37 °F, low 13 °F 37°13° FebMarch: average high 45 °F, low 20 °F 45°20° MarApril: average high 54 °F, low 27 °F 54°27° AprMay: average high 65 °F, low 34 °F 65°34° MayJune: average high 72 °F, low 41 °F 72°41° JunJuly: average high 83 °F, low 44 °F 83°44° JulAugust: average high 83 °F, low 43 °F 83°43° AugSeptember: average high 73 °F, low 37 °F 73°37° SepOctober: average high 56 °F, low 29 °F 56°29° OctNovember: average high 40 °F, low 21 °F 40°21° NovDecember: average high 31 °F, low 13 °F 31°13° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 2.63 in precipitation, 30.4 in snowfall 2.6❄30 JanFebruary: 1.92 in precipitation, 18.5 in snowfall 1.9❄19 FebMarch: 1.44 in precipitation, 15.2 in snowfall 1.4❄15 MarApril: 1.37 in precipitation, 4.5 in snowfall 1.4❄5 AprMay: 1.88 in precipitation, 0.7 in snowfall 1.9❄1 MayJune: 2.31 in precipitation, 0.4 in snowfall 2.3 JunJuly: 1.07 in precipitation 1.1 JulAugust: 0.96 in precipitation 1.0 AugSeptember: 1.19 in precipitation 1.2 SepOctober: 1.96 in precipitation, 2.3 in snowfall 2.0❄2 OctNovember: 2.52 in precipitation, 18 in snowfall 2.5❄18 NovDecember: 2.35 in precipitation, 28.9 in snowfall 2.4❄29 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Seeley Lake Rs, MT (within 1 mile); precipitation: Seeley Lake Rs, MT (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

598235b
Bonner, MT · 18 mi
598265a
Condon, MT · 18 mi
598656a
Saint Ignatius, MT · 23 mi
598025b
Missoula, MT · 28 mi
598515b
Milltown, MT · 29 mi
598076a
Missoula, MT · 29 mi
598065b
Missoula, MT · 32 mi
598125b
Missoula, MT · 32 mi

Montana planting zones →

Questions about 59868

What planting zone is ZIP code 59868?

ZIP code 59868 (Seeley Lake, 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 Seeley Lake, MT?

The median last spring frost (32 °F) near 59868 is May 20; after June 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lindbergh Lake station.

When is the first frost in Seeley Lake, MT?

The median first fall frost near 59868 is September 22, giving a median frost-free growing season of 120 days.

When should I plant tomatoes in 59868?

Start tomato seeds indoors around Mar 25 – Apr 8 and set transplants outside around May 27 – Jun 10, one to three weeks after the median last frost.

How much rain and snow does 59868 get?

About 21.6 inches of precipitation a year and 119 inches of snowfall (NOAA 1991–2020 normals, Seeley Lake Rs station).

How hot do summers get in Seeley Lake, MT?

The average high peaks at 83 °F in July, with about 15 days a year at 90 °F or more.

What kind of soil does 59868 have?

The USDA soil survey maps Glaciercreek at the center of ZIP 59868: slightly decomposed plant material, excessively drained, pH about 6.5 (neutral).

Did spring come early in Seeley Lake, MT in 2026?

Spring leaf-out near 59868 came on Apr 18 in 2026, 8 days earlier than the 1991–2020 average (Apr 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Seeley Lake, MT?

Long-day onions: the longest day near 59868 is 15 h 56 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 59868 change?

Yes. The 2012 USDA map put 59868 in zone 4a; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.