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

Planting zone for 59749 — Sheridan, MT

ZIP code 59749 (Sheridan, Madison County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 24 and the first fall frost September 22.

Where ZIP 59749 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 24
First frostSep 22
2012 zone4b

Was 4b 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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Sheridan, 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 Sheridan, MT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 24median — 50% chance of a later frost
Safe for tender plantsJune 13only 10% chance of frost after
First fall frostSeptember 22median — 10% chance by Sep 6
Growing season117 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 10 and returns around October 3.

From the NOAA station Laurin 2ne, MT — 6 miles away, elevation 5,197 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 59749

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 12 – Apr 26
SpinachSow outdoors · Apr 12 – May 3
Broccoli, cabbageStart indoors · Mar 15 – Mar 29
Broccoli, cabbageTransplant · May 3 – May 17
Onion setsPlant outdoors · Apr 26 – May 10
PotatoesPlant outdoors · May 3 – May 17
LettuceSow outdoors · Apr 26 – May 10
Carrots, beetsSow outdoors · May 3 – May 17
TomatoesStart indoors · Mar 29 – Apr 12
TomatoesTransplant · May 31 – Jun 14
Peppers, eggplantStart indoors · Mar 15 – Mar 29
Peppers, eggplantTransplant · Jun 7 – Jun 21
BeansSow outdoors · May 31 – Jun 14
Sweet cornSow outdoors · May 31 – Jun 14
Cucumbers, squashSow outdoors · May 31 – Jun 14
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 24) 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 59749 came on Apr 18 — 21 days earlier than the 1991–2020 average (May 9).

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 Sheridan, MT.

Soil in Sheridan, MT

The soil mapped at the center of ZIP 59749 is Matcher — stony sandy loam, somewhat excessively drained.

TextureStony sandy loamdrains and warms fast; dries out and needs more feeding
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Matcher-Leighcan-Cowood families, complex, mountain ridgetops.

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 59749; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sheridan, MT

Summer high80 °Faverage high, July
Winter low14 °Faverage low, December
Hot days1days a year at 90 °F or more
Freezing nights184nights a year at 32 °F or less
Growing degree days1,489base 50 °F — the season’s usable heat
Longest day15 h 41 mindaylight on June 21
Shortest day8 h 42 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation14.5 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 34 °F, low 15 °F 34°15° JanFebruary: average high 36 °F, low 16 °F 36°16° FebMarch: average high 46 °F, low 24 °F 46°24° MarApril: average high 53 °F, low 29 °F 53°29° AprMay: average high 62 °F, low 37 °F 62°37° MayJune: average high 70 °F, low 44 °F 70°44° JunJuly: average high 80 °F, low 50 °F 80°50° JulAugust: average high 79 °F, low 50 °F 79°50° AugSeptember: average high 69 °F, low 42 °F 69°42° SepOctober: average high 55 °F, low 32 °F 55°32° OctNovember: average high 42 °F, low 22 °F 42°22° NovDecember: average high 32 °F, low 14 °F 32°14° Dec

Precipitation by month inches

0″1″2″3″January: 0.41 in precipitation 0.4 JanFebruary: 0.57 in precipitation 0.6 FebMarch: 0.98 in precipitation 1.0 MarApril: 1.33 in precipitation 1.3 AprMay: 2.41 in precipitation 2.4 MayJune: 2.94 in precipitation 2.9 JunJuly: 1.33 in precipitation 1.3 JulAugust: 0.98 in precipitation 1.0 AugSeptember: 1.13 in precipitation 1.1 SepOctober: 1.06 in precipitation 1.1 OctNovember: 0.56 in precipitation 0.6 NovDecember: 0.77 in precipitation 0.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Laurin 2ne, MT (6 mi away); precipitation: Sheridan 1.4 Ene, MT (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

597405a
Mc Allister, MT · 13 mi
597555a
Virginia City, MT · 14 mi
597545a
Twin Bridges, MT · 14 mi
597355a
Harrison, MT · 17 mi
597475a
Pony, MT · 18 mi
597515a
Silver Star, MT · 20 mi
597295a
Ennis, MT · 22 mi
597455a
Norris, MT · 24 mi

Montana planting zones →

Questions about 59749

What planting zone is ZIP code 59749?

ZIP code 59749 (Sheridan, 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 Sheridan, MT?

The median last spring frost (32 °F) near 59749 is May 24; after June 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Laurin 2ne station.

When is the first frost in Sheridan, MT?

The median first fall frost near 59749 is September 22, giving a median frost-free growing season of 117 days.

When should I plant tomatoes in 59749?

Start tomato seeds indoors around Mar 29 – Apr 12 and set transplants outside around May 31 – Jun 14, one to three weeks after the median last frost.

How much rain and snow does 59749 get?

About 14.5 inches of precipitation a year (NOAA 1991–2020 normals, Sheridan 1.4 Ene station).

How hot do summers get in Sheridan, MT?

The average high peaks at 80 °F in July, with about 1 days a year at 90 °F or more.

What kind of soil does 59749 have?

The USDA soil survey maps Matcher at the center of ZIP 59749: stony sandy loam, somewhat excessively drained, pH about 5.0 (strongly acidic).

Did spring come early in Sheridan, MT in 2026?

Spring leaf-out near 59749 came on Apr 18 in 2026, 21 days earlier than the 1991–2020 average (May 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Sheridan, MT?

Long-day onions: the longest day near 59749 is 15 h 41 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 59749 change?

Yes. The 2012 USDA map put 59749 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.