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

Planting zone for 83444 — Roberts, ID

ZIP code 83444 (Roberts, Jefferson County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is June 3 and the first fall frost September 11.

Where ZIP 83444 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 frostJun 3
First frostSep 11
2012 zone5a

Same zone as on the 2012 map. 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 Roberts, 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 Roberts, ID

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJune 3median — 50% chance of a later frost
Safe for tender plantsJune 21only 10% chance of frost after
First fall frostSeptember 11median — 10% chance by Aug 30
Growing season98 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 14 and returns around September 21.

From the NOAA station Hamer 4 Nw, ID — 17 miles away, elevation 4,790 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 83444

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 22 – May 6
SpinachSow outdoors · Apr 22 – May 13
Broccoli, cabbageStart indoors · Mar 25 – Apr 8
Broccoli, cabbageTransplant · May 13 – May 27
Onion setsPlant outdoors · May 6 – May 20
PotatoesPlant outdoors · May 13 – May 27
LettuceSow outdoors · May 6 – May 20
Carrots, beetsSow outdoors · May 13 – May 27
TomatoesStart indoors · Apr 8 – Apr 22
TomatoesTransplant · Jun 10 – Jun 24
Peppers, eggplantStart indoors · Mar 25 – Apr 8
Peppers, eggplantTransplant · Jun 17 – Jul 1
BeansSow outdoors · Jun 10 – Jun 24
Sweet cornSow outdoors · Jun 10 – Jun 24
Cucumbers, squashSow outdoors · Jun 10 – Jun 24
Fall lettuce, spinachSow outdoors · Jul 17 – Jul 31
GarlicPlant cloves · Aug 28 – Oct 2
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 3) and first fall frost (Sep 11) 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 83444 came on Mar 27 — 22 days earlier than the 1991–2020 average (Apr 18).

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 Idaho

536 plants native to the lower 48 states, recorded in Idaho, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

Trees 28

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 92

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 258

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 148

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 Roberts, ID.

Soil in Roberts, ID

The soil mapped at the center of ZIP 83444 is Pancheri — 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 matter1.5%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Pancheri silt loam, 2 to 30 percent slopes, stony.

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 83444; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Roberts, ID

Summer high89 °Faverage high, July
Winter low7 °Faverage low, January
Hot days31days a year at 90 °F or more
Freezing nights205nights a year at 32 °F or less
Growing degree days1,964base 50 °F — the season’s usable heat
Longest day15 h 27 mindaylight on June 21
Shortest day8 h 55 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation8.9 inper year, rain and melted snow
Snowfall20 inper year; 69 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 29 °F, low 7 °F 29°7° JanFebruary: average high 36 °F, low 11 °F 36°11° FebMarch: average high 49 °F, low 22 °F 49°22° MarApril: average high 60 °F, low 29 °F 60°29° AprMay: average high 70 °F, low 37 °F 70°37° MayJune: average high 79 °F, low 44 °F 79°44° JunJuly: average high 89 °F, low 49 °F 89°49° JulAugust: average high 87 °F, low 47 °F 87°47° AugSeptember: average high 78 °F, low 39 °F 78°39° SepOctober: average high 62 °F, low 28 °F 62°28° OctNovember: average high 44 °F, low 17 °F 44°17° NovDecember: average high 30 °F, low 9 °F 30°9° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″January: 0.72 in precipitation, 5.8 in snowfall 0.7❄6 JanFebruary: 0.44 in precipitation, 3.5 in snowfall 0.4❄4 FebMarch: 0.50 in precipitation, 1.7 in snowfall 0.5❄2 MarApril: 0.94 in precipitation, 0.8 in snowfall 0.9❄1 AprMay: 1.47 in precipitation 1.5 MayJune: 1.11 in precipitation 1.1 JunJuly: 0.52 in precipitation 0.5 JulAugust: 0.51 in precipitation 0.5 AugSeptember: 0.63 in precipitation 0.6 SepOctober: 0.73 in precipitation, 0.1 in snowfall 0.7 OctNovember: 0.56 in precipitation, 1.7 in snowfall 0.6❄2 NovDecember: 0.80 in precipitation, 6.8 in snowfall 0.8❄7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Hamer 4 Nw, ID (17 mi away); precipitation: Hamer 4 Nw, ID (17 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.

834504b
Terreton, ID · 10 mi
834315a
Lewisville, ID · 14 mi
834025b
Idaho Falls, ID · 15 mi
834345a
Menan, ID · 15 mi
834255a
Hamer, ID · 15 mi
834035b
Idaho Falls, ID · 22 mi
834055b
Idaho Falls, ID · 22 mi
834155b
Idaho Falls, ID · 22 mi

Idaho planting zones →

Questions about 83444

What planting zone is ZIP code 83444?

ZIP code 83444 (Roberts, ID) 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 Roberts, ID?

The median last spring frost (32 °F) near 83444 is June 3; after June 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hamer 4 Nw station.

When is the first frost in Roberts, ID?

The median first fall frost near 83444 is September 11, giving a median frost-free growing season of 98 days.

When should I plant tomatoes in 83444?

Start tomato seeds indoors around Apr 8 – Apr 22 and set transplants outside around Jun 10 – Jun 24, one to three weeks after the median last frost.

How much rain and snow does 83444 get?

About 8.9 inches of precipitation a year and 20 inches of snowfall (NOAA 1991–2020 normals, Hamer 4 Nw station).

How hot do summers get in Roberts, ID?

The average high peaks at 89 °F in July, with about 31 days a year at 90 °F or more.

What kind of soil does 83444 have?

The USDA soil survey maps Pancheri at the center of ZIP 83444: silt loam, well drained, pH about 7.9 (alkaline).

Did spring come early in Roberts, ID in 2026?

Spring leaf-out near 83444 came on Mar 27 in 2026, 22 days earlier than the 1991–2020 average (Apr 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Roberts, ID?

Long-day onions: the longest day near 83444 is 15 h 27 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).