Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 83448 — Sugar City, ID

ZIP code 83448 (Sugar City, Madison County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 29 and the first fall frost September 13.

Where ZIP 83448 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 29

First frostSep 13

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 Sugar City, 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 Sugar City, ID

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMay 29median — 50% chance of a later frost

Safe for tender plantsJune 18only 10% chance of frost after

First fall frostSeptember 13median — 10% chance by Aug 30

Growing season106 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 9 and returns around September 25.

From the NOAA station Sugar City, ID — 3 miles away, elevation 4,925 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 83448

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 17 – May 1

SpinachSow outdoors · Apr 17 – May 8

Broccoli, cabbageStart indoors · Mar 20 – Apr 3

Broccoli, cabbageTransplant · May 8 – May 22

Onion setsPlant outdoors · May 1 – May 15

PotatoesPlant outdoors · May 8 – May 22

LettuceSow outdoors · May 1 – May 15

Carrots, beetsSow outdoors · May 8 – May 22

TomatoesStart indoors · Apr 3 – Apr 17

TomatoesTransplant · Jun 5 – Jun 19

Peppers, eggplantStart indoors · Mar 20 – Apr 3

Peppers, eggplantTransplant · Jun 12 – Jun 26

BeansSow outdoors · Jun 5 – Jun 19

Sweet cornSow outdoors · Jun 5 – Jun 19

Cucumbers, squashSow outdoors · Jun 5 – Jun 19

Fall lettuce, spinachSow outdoors · Jul 19 – Aug 2

GarlicPlant cloves · Aug 30 – Oct 4

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 29) and first fall frost (Sep 13) 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 83448 came on Mar 27 — 23 days earlier than the 1991–2020 average (Apr 19).

average
Apr 192026
Mar 27

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.

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 Sugar City, ID.

Soil in Sugar City, ID

The soil mapped at the center of ZIP 83448 is Blackfoot — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH7.9alkaline; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2%moderate

Hydrologic groupCwater soaks in slowly

Farmland classPrime farmland if irrigated and drainedUSDA classification

Map unit: Blackfoot silt loam.

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 83448; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sugar City, ID

Summer high84 °Faverage high, August

Winter low9 °Faverage low, January

Hot days8days a year at 90 °F or more

Freezing nights193nights a year at 32 °F or less

Growing degree days1,550base 50 °F — the season’s usable heat

Longest day15 h 28 mindaylight on June 21

Shortest day8 h 54 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation12 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Sugar City, ID (3 mi away); precipitation: Rexburg Madison Co. Airport, ID (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

Saint Anthony, ID · 13 mi

834215a

Chester, ID · 13 mi

Idaho planting zones →

Questions about 83448

What planting zone is ZIP code 83448?

ZIP code 83448 (Sugar City, 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 Sugar City, ID?

The median last spring frost (32 °F) near 83448 is May 29; after June 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Sugar City station.

When is the first frost in Sugar City, ID?

The median first fall frost near 83448 is September 13, giving a median frost-free growing season of 106 days.

When should I plant tomatoes in 83448?

Start tomato seeds indoors around Apr 3 – Apr 17 and set transplants outside around Jun 5 – Jun 19, one to three weeks after the median last frost.

How much rain and snow does 83448 get?

About 12 inches of precipitation a year (NOAA 1991–2020 normals, Rexburg Madison Co. Airport station).

How hot do summers get in Sugar City, ID?

The average high peaks at 84 °F in August, with about 8 days a year at 90 °F or more.

What kind of soil does 83448 have?

The USDA soil survey maps Blackfoot at the center of ZIP 83448: silt loam, somewhat poorly drained, pH about 7.9 (alkaline).

Did spring come early in Sugar City, ID in 2026?

Spring leaf-out near 83448 came on Mar 27 in 2026, 23 days earlier than the 1991–2020 average (Apr 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Sugar City, ID?

Long-day onions: the longest day near 83448 is 15 h 28 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).