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

Planting zone for 59920 — Kila, MT

ZIP code 59920 (Kila, Flathead County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 12 and the first fall frost September 25.

Where ZIP 59920 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.

Zone5b−15 to −10 °F
Coldest night−26.1 to −23.3 °C
Last frostMay 12
First frostSep 25
2012 zone5a

Was 5a 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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Kila, 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 Kila, MT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 12median — 50% chance of a later frost
Safe for tender plantsMay 26only 10% chance of frost after
First fall frostSeptember 25median — 10% chance by Sep 9
Growing season134 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 28 and returns around October 5.

From the NOAA station Creston, MT — 25 miles away, elevation 2,936 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 59920

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 31 – Apr 14
SpinachSow outdoors · Mar 31 – Apr 21
Broccoli, cabbageStart indoors · Mar 3 – Mar 17
Broccoli, cabbageTransplant · Apr 21 – May 5
Onion setsPlant outdoors · Apr 14 – Apr 28
PotatoesPlant outdoors · Apr 21 – May 5
LettuceSow outdoors · Apr 14 – Apr 28
Carrots, beetsSow outdoors · Apr 21 – May 5
TomatoesStart indoors · Mar 17 – Mar 31
TomatoesTransplant · May 19 – Jun 2
Peppers, eggplantStart indoors · Mar 3 – Mar 17
Peppers, eggplantTransplant · May 26 – Jun 9
BeansSow outdoors · May 19 – Jun 2
Sweet cornSow outdoors · May 19 – Jun 2
Cucumbers, squashSow outdoors · May 19 – Jun 2
Fall lettuce, spinachSow outdoors · Jul 31 – Aug 14
GarlicPlant cloves · Sep 11 – Oct 16
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 12) and first fall frost (Sep 25) 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 59920 came on Apr 24 — 6 days earlier than the 1991–2020 average (Apr 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 5b in Montana

561 plants native to the lower 48 states, recorded in Montana, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. Each links to its USDA PLANTS profile.

Trees 28

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 97

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 259

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 164

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 Kila, MT.

Soil in Kila, MT

The soil mapped at the center of ZIP 59920 is Dystric Cryochrepts — moderately decomposed plant material.

TextureModerately decomposed plant materialtop layer
pH6.5neutral; most vegetables like 6.0–7.0
Organic matter33%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Dystric Cryochrepts, till substratum-Dystric Cryochrepts, residuum substratum complex, hilly.

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 59920; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Kila, MT

Summer high81 °Faverage high, July
Winter low18 °Faverage low, January
Hot days7days a year at 90 °F or more
Freezing nights179nights a year at 32 °F or less
Growing degree days1,586base 50 °F — the season’s usable heat
Longest day16 h 03 mindaylight on June 21
Shortest day8 h 22 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation17.2 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 32 °F, low 18 °F 32°18° JanFebruary: average high 37 °F, low 19 °F 37°19° FebMarch: average high 45 °F, low 26 °F 45°26° MarApril: average high 55 °F, low 32 °F 55°32° AprMay: average high 65 °F, low 40 °F 65°40° MayJune: average high 71 °F, low 47 °F 71°47° JunJuly: average high 81 °F, low 51 °F 81°51° JulAugust: average high 81 °F, low 49 °F 81°49° AugSeptember: average high 70 °F, low 41 °F 70°41° SepOctober: average high 56 °F, low 32 °F 56°32° OctNovember: average high 41 °F, low 26 °F 41°26° NovDecember: average high 33 °F, low 20 °F 33°20° Dec

Precipitation by month inches

0″1″2″3″January: 1.24 in precipitation 1.2 JanFebruary: 0.90 in precipitation 0.9 FebMarch: 1.04 in precipitation 1.0 MarApril: 1.38 in precipitation 1.4 AprMay: 1.73 in precipitation 1.7 MayJune: 2.40 in precipitation 2.4 JunJuly: 1.54 in precipitation 1.5 JulAugust: 0.82 in precipitation 0.8 AugSeptember: 1.48 in precipitation 1.5 SepOctober: 1.59 in precipitation 1.6 OctNovember: 1.58 in precipitation 1.6 NovDecember: 1.48 in precipitation 1.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Creston, MT (25 mi away); precipitation: Kalispell 10.1 Sw, MT (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

599254b
Marion, MT · 11 mi
599296a
Proctor, MT · 11 mi
599156a
Elmo, MT · 16 mi
599146a
Dayton, MT · 17 mi
599316a
Rollins, MT · 17 mi
599035b
Kalispell, MT · 17 mi
599015b
Kalispell, MT · 18 mi
599045b
Kalispell, MT · 23 mi

Montana planting zones →

Questions about 59920

What planting zone is ZIP code 59920?

ZIP code 59920 (Kila, MT) is in USDA hardiness zone 5b on the 2023 map: the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C).

When is the last frost in Kila, MT?

The median last spring frost (32 °F) near 59920 is May 12; after May 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Creston station.

When is the first frost in Kila, MT?

The median first fall frost near 59920 is September 25, giving a median frost-free growing season of 134 days.

When should I plant tomatoes in 59920?

Start tomato seeds indoors around Mar 17 – Mar 31 and set transplants outside around May 19 – Jun 2, one to three weeks after the median last frost.

How much rain and snow does 59920 get?

About 17.2 inches of precipitation a year (NOAA 1991–2020 normals, Kalispell 10.1 Sw station).

How hot do summers get in Kila, MT?

The average high peaks at 81 °F in July, with about 7 days a year at 90 °F or more.

What kind of soil does 59920 have?

The USDA soil survey maps Dystric Cryochrepts at the center of ZIP 59920: moderately decomposed plant material, pH about 6.5 (neutral).

Did spring come early in Kila, MT in 2026?

Spring leaf-out near 59920 came on Apr 24 in 2026, 6 days earlier than the 1991–2020 average (Apr 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Kila, MT?

Long-day onions: the longest day near 59920 is 16 h 03 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 59920 change?

Yes. The 2012 USDA map put 59920 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.