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

Planting zone for 84031 — Hanna, UT

ZIP code 84031 (Hanna, Duchesne County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is June 11 and the first fall frost September 18.

Where ZIP 84031 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 11

First frostSep 18

2012 zone5b

Was 5b on the 2012 map — half a zone colder 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 Hanna, UT…

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 Hanna, UT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 11median — 50% chance of a later frost

Safe for tender plantsJune 24only 10% chance of frost after

First fall frostSeptember 18median — 10% chance by Sep 5

Growing season97 daysfrost-free, median

A hard freeze (28 °F) usually ends around June 1 and returns around September 28.

From the NOAA station Moon Lake, UT — 11 miles away, elevation 8,127 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 84031

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 30 – May 14

SpinachSow outdoors · Apr 30 – May 21

Broccoli, cabbageStart indoors · Apr 2 – Apr 16

Broccoli, cabbageTransplant · May 21 – Jun 4

Onion setsPlant outdoors · May 14 – May 28

PotatoesPlant outdoors · May 21 – Jun 4

LettuceSow outdoors · May 14 – May 28

Carrots, beetsSow outdoors · May 21 – Jun 4

TomatoesStart indoors · Apr 16 – Apr 30

TomatoesTransplant · Jun 18 – Jul 2

Peppers, eggplantStart indoors · Apr 2 – Apr 16

Peppers, eggplantTransplant · Jun 25 – Jul 9

BeansSow outdoors · Jun 18 – Jul 2

Sweet cornSow outdoors · Jun 18 – Jul 2

Cucumbers, squashSow outdoors · Jun 18 – Jul 2

Fall lettuce, spinachSow outdoors · Jul 24 – Aug 7

GarlicPlant cloves · Sep 4 – Oct 9

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 11) and first fall frost (Sep 18) 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 84031 came on May 23 — 4 days earlier than the 1991–2020 average (May 27).

average
May 272026
May 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 Utah

498 plants native to the lower 48 states, recorded in Utah, 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 Hanna, UT.

Soil in Hanna, UT

The center of ZIP 84031 is mapped as No Digital Data Available: 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 84031; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hanna, UT

Summer high78 °Faverage high, August

Winter low7 °Faverage low, January

Hot days0days a year at 90 °F or more

Freezing nights230nights a year at 32 °F or less

Growing degree days1,194base 50 °F — the season’s usable heat

Longest day15 h 05 mindaylight on June 21

Shortest day9 h 15 mindaylight on December 21

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

Precipitation33.3 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: Moon Lake, UT (11 mi away); precipitation: Brown Duck, UT (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

7 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

Mountain Home, UT · 22 mi

Utah planting zones →

Questions about 84031

What planting zone is ZIP code 84031?

ZIP code 84031 (Hanna, UT) 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 Hanna, UT?

The median last spring frost (32 °F) near 84031 is June 11; after June 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Moon Lake station.

When is the first frost in Hanna, UT?

The median first fall frost near 84031 is September 18, giving a median frost-free growing season of 97 days.

When should I plant tomatoes in 84031?

Start tomato seeds indoors around Apr 16 – Apr 30 and set transplants outside around Jun 18 – Jul 2, one to three weeks after the median last frost.

How much rain and snow does 84031 get?

About 33.3 inches of precipitation a year (NOAA 1991–2020 normals, Brown Duck station).

How hot do summers get in Hanna, UT?

The average high peaks at 78 °F in August, with about 0 days a year at 90 °F or more.

Did spring come early in Hanna, UT in 2026?

Spring leaf-out near 84031 came on May 23 in 2026, 4 days earlier than the 1991–2020 average (May 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hanna, UT?

Long-day onions: the longest day near 84031 is 15 h 05 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 84031 change?

Yes. The 2012 USDA map put 84031 in zone 5b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.