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

Planting zone for 83648 — Mountain Home Afb, ID

ZIP code 83648 (Mountain Home Afb, Elmore County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 2 and the first fall frost October 8.

Where ZIP 83648 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostMay 2
First frostOct 8
2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mountain Home Afb, ID…

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 Mountain Home Afb, ID

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 2median — 50% chance of a later frost
Safe for tender plantsMay 23only 10% chance of frost after
First fall frostOctober 8median — 10% chance by Sep 25
Growing season157 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 18 and returns around October 20.

From the NOAA station Mtn Home, ID — 9 miles away, elevation 3,140 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 83648

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 21 – Apr 4
SpinachSow outdoors · Mar 21 – Apr 11
Broccoli, cabbageStart indoors · Feb 21 – Mar 7
Broccoli, cabbageTransplant · Apr 11 – Apr 25
Onion setsPlant outdoors · Apr 4 – Apr 18
PotatoesPlant outdoors · Apr 11 – Apr 25
LettuceSow outdoors · Apr 4 – Apr 18
Carrots, beetsSow outdoors · Apr 11 – Apr 25
TomatoesStart indoors · Mar 7 – Mar 21
TomatoesTransplant · May 9 – May 23
Peppers, eggplantStart indoors · Feb 21 – Mar 7
Peppers, eggplantTransplant · May 16 – May 30
BeansSow outdoors · May 9 – May 23
Sweet cornSow outdoors · May 9 – May 23
Cucumbers, squashSow outdoors · May 9 – May 23
Fall lettuce, spinachSow outdoors · Aug 13 – Aug 27
GarlicPlant cloves · Sep 24 – Oct 29
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 2) and first fall frost (Oct 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 83648 came on Mar 7 — 16 days earlier than the 1991–2020 average (Mar 23).

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 7a in Idaho

575 plants native to the lower 48 states, recorded in Idaho, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Trees 30

balsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fblue spruce100 ft · blooms late spring · medium shade tolerance · to −38 °Fboxelder60 ft · blooms early spring · low shade tolerance · to −46 °FDouglas-fir200 ft · blooms mid spring · medium shade tolerance · to −33 °FEngelmann spruce120 ft · blooms late spring · low shade tolerance · to −50 °F

Shrubs 101

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 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FBarclay's willow15 ft · high shade tolerance · to −43 °Fbeaked hazelnut15 ft · blooms early spring · low shade tolerance · to −47 °F

Wildflowers & perennials 277

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 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °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 1

western 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 Mountain Home Afb, ID.

Soil in Mountain Home Afb, ID

The soil mapped at the center of ZIP 83648 is Bahem — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH7.9alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupBwater soaks in moderately
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Bahem 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 83648; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mountain Home Afb, ID

Summer high95 °Faverage high, July
Winter low23 °Faverage low, January
Hot days65days a year at 90 °F or more
Freezing nights139nights a year at 32 °F or less
Growing degree days3,171base 50 °F — the season’s usable heat
Longest day15 h 22 mindaylight on June 21
Shortest day9 h 00 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation7.4 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 40 °F, low 23 °F 40°23° JanFebruary: average high 47 °F, low 26 °F 47°26° FebMarch: average high 56 °F, low 30 °F 56°30° MarApril: average high 63 °F, low 36 °F 63°36° AprMay: average high 74 °F, low 45 °F 74°45° MayJune: average high 84 °F, low 52 °F 84°52° JunJuly: average high 95 °F, low 60 °F 95°60° JulAugust: average high 93 °F, low 58 °F 93°58° AugSeptember: average high 82 °F, low 48 °F 82°48° SepOctober: average high 67 °F, low 37 °F 67°37° OctNovember: average high 50 °F, low 28 °F 50°28° NovDecember: average high 39 °F, low 23 °F 39°23° Dec

Precipitation by month inches

0″1″2″January: 0.97 in precipitation 1.0 JanFebruary: 0.48 in precipitation 0.5 FebMarch: 0.73 in precipitation 0.7 MarApril: 0.72 in precipitation 0.7 AprMay: 1.17 in precipitation 1.2 MayJune: 0.60 in precipitation 0.6 JunJuly: 0.14 in precipitation 0.1 JulAugust: 0.13 in precipitation 0.1 AugSeptember: 0.26 in precipitation 0.3 SepOctober: 0.62 in precipitation 0.6 OctNovember: 0.61 in precipitation 0.6 NovDecember: 0.95 in precipitation 0.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mtn Home, ID (9 mi away); precipitation: Bruneau, ID (12 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.

836247a
Grand View, ID · 17 mi
836277a
Hammett, ID · 19 mi
836476b
Mountain Home, ID · 30 mi
837087a
Boise, ID · 34 mi
837117a
Boise, ID · 34 mi
837157a
Boise, ID · 34 mi
837177a
Boise, ID · 34 mi
837197a
Boise, ID · 34 mi

Idaho planting zones →

Questions about 83648

What planting zone is ZIP code 83648?

ZIP code 83648 (Mountain Home Afb, ID) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Mountain Home Afb, ID?

The median last spring frost (32 °F) near 83648 is May 2; after May 23 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mtn Home station.

When is the first frost in Mountain Home Afb, ID?

The median first fall frost near 83648 is October 8, giving a median frost-free growing season of 157 days.

When should I plant tomatoes in 83648?

Start tomato seeds indoors around Mar 7 – Mar 21 and set transplants outside around May 9 – May 23, one to three weeks after the median last frost.

How much rain and snow does 83648 get?

About 7.4 inches of precipitation a year (NOAA 1991–2020 normals, Bruneau station).

How hot do summers get in Mountain Home Afb, ID?

The average high peaks at 95 °F in July, with about 65 days a year at 90 °F or more.

What kind of soil does 83648 have?

The USDA soil survey maps Bahem at the center of ZIP 83648: silt loam, well drained, pH about 7.9 (alkaline).

Did spring come early in Mountain Home Afb, ID in 2026?

Spring leaf-out near 83648 came on Mar 7 in 2026, 16 days earlier than the 1991–2020 average (Mar 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mountain Home Afb, ID?

Long-day onions: the longest day near 83648 is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 83648 change?

Yes. The 2012 USDA map put 83648 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.