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

Planting zone for 83445 — Saint Anthony, ID

ZIP code 83445 (Saint Anthony, Fremont County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 17 and the first fall frost September 22.

Where ZIP 83445 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 17
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 Saint Anthony, 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 Saint Anthony, ID

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 17median — 50% chance of a later frost
Safe for tender plantsJune 10only 10% chance of frost after
First fall frostSeptember 22median — 10% chance by Sep 5
Growing season126 daysfrost-free, median

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

From the NOAA station Saint Anthony, ID — 7 miles away, elevation 4,912 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 83445

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 5 – Apr 19
SpinachSow outdoors · Apr 5 – Apr 26
Broccoli, cabbageStart indoors · Mar 8 – Mar 22
Broccoli, cabbageTransplant · Apr 26 – May 10
Onion setsPlant outdoors · Apr 19 – May 3
PotatoesPlant outdoors · Apr 26 – May 10
LettuceSow outdoors · Apr 19 – May 3
Carrots, beetsSow outdoors · Apr 26 – May 10
TomatoesStart indoors · Mar 22 – Apr 5
TomatoesTransplant · May 24 – Jun 7
Peppers, eggplantStart indoors · Mar 8 – Mar 22
Peppers, eggplantTransplant · May 31 – Jun 14
BeansSow outdoors · May 24 – Jun 7
Sweet cornSow outdoors · May 24 – Jun 7
Cucumbers, squashSow outdoors · May 24 – Jun 7
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 17) 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 83445 came on Mar 28 — 26 days earlier than the 1991–2020 average (Apr 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 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 Saint Anthony, ID.

Soil in Saint Anthony, ID

The center of ZIP 83445 is mapped as Dune land: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 83445; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Saint Anthony, ID

Summer high83 °Faverage high, July
Winter low12 °Faverage low, January
Hot days10days a year at 90 °F or more
Freezing nights206nights a year at 32 °F or less
Growing degree days1,721base 50 °F — the season’s usable heat
Longest day15 h 29 mindaylight on June 21
Shortest day8 h 53 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation14.8 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 28 °F, low 12 °F 28°12° JanFebruary: average high 32 °F, low 14 °F 32°14° FebMarch: average high 44 °F, low 23 °F 44°23° MarApril: average high 55 °F, low 31 °F 55°31° AprMay: average high 65 °F, low 39 °F 65°39° MayJune: average high 73 °F, low 45 °F 73°45° JunJuly: average high 83 °F, low 50 °F 83°50° JulAugust: average high 83 °F, low 49 °F 83°49° AugSeptember: average high 73 °F, low 41 °F 73°41° SepOctober: average high 58 °F, low 32 °F 58°32° OctNovember: average high 41 °F, low 22 °F 41°22° NovDecember: average high 29 °F, low 13 °F 29°13° Dec

Precipitation by month inches

0″1″2″January: 1.65 in precipitation 1.6 JanFebruary: 0.89 in precipitation 0.9 FebMarch: 1.05 in precipitation 1.1 MarApril: 1.33 in precipitation 1.3 AprMay: 1.95 in precipitation 1.9 MayJune: 1.74 in precipitation 1.7 JunJuly: 0.71 in precipitation 0.7 JulAugust: 0.62 in precipitation 0.6 AugSeptember: 1.06 in precipitation 1.1 SepOctober: 1.29 in precipitation 1.3 OctNovember: 1.12 in precipitation 1.1 NovDecember: 1.41 in precipitation 1.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Saint Anthony, ID (7 mi away); precipitation: Saint Anthony, ID (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

834385a
Parker, ID · 5 mi
834215a
Chester, ID · 10 mi
834515a
Teton, ID · 13 mi
834485a
Sugar City, ID · 13 mi
834605a
Rexburg, ID · 15 mi
834405a
Rexburg, ID · 16 mi
834415a
Rexburg, ID · 18 mi
834365a
Newdale, ID · 19 mi

Idaho planting zones →

Questions about 83445

What planting zone is ZIP code 83445?

ZIP code 83445 (Saint Anthony, 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 Saint Anthony, ID?

The median last spring frost (32 °F) near 83445 is May 17; after June 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Saint Anthony station.

When is the first frost in Saint Anthony, ID?

The median first fall frost near 83445 is September 22, giving a median frost-free growing season of 126 days.

When should I plant tomatoes in 83445?

Start tomato seeds indoors around Mar 22 – Apr 5 and set transplants outside around May 24 – Jun 7, one to three weeks after the median last frost.

How much rain and snow does 83445 get?

About 14.8 inches of precipitation a year (NOAA 1991–2020 normals, Saint Anthony station).

How hot do summers get in Saint Anthony, ID?

The average high peaks at 83 °F in July, with about 10 days a year at 90 °F or more.

Did spring come early in Saint Anthony, ID in 2026?

Spring leaf-out near 83445 came on Mar 28 in 2026, 26 days earlier than the 1991–2020 average (Apr 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Saint Anthony, ID?

Long-day onions: the longest day near 83445 is 15 h 29 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 83445 change?

Yes. The 2012 USDA map put 83445 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.