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

Planting zone for 84635 — Hinckley, UT

ZIP code 84635 (Hinckley, Millard County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 14 and the first fall frost September 30.

Where ZIP 84635 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.

Zone6a−10 to −5 °F

Coldest night−23.3 to −20.6 °C

Last frostMay 14

First frostSep 30

2012 zone6a

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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Hinckley, 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 Hinckley, UT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 14median — 50% chance of a later frost

Safe for tender plantsMay 31only 10% chance of frost after

First fall frostSeptember 30median — 10% chance by Sep 16

Growing season137 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 1 and returns around October 10.

From the NOAA station Deseret, UT — 8 miles away, elevation 4,590 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 84635

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 2 – Apr 16

SpinachSow outdoors · Apr 2 – Apr 23

Broccoli, cabbageStart indoors · Mar 5 – Mar 19

Broccoli, cabbageTransplant · Apr 23 – May 7

Onion setsPlant outdoors · Apr 16 – Apr 30

PotatoesPlant outdoors · Apr 23 – May 7

LettuceSow outdoors · Apr 16 – Apr 30

Carrots, beetsSow outdoors · Apr 23 – May 7

TomatoesStart indoors · Mar 19 – Apr 2

TomatoesTransplant · May 21 – Jun 4

Peppers, eggplantStart indoors · Mar 5 – Mar 19

Peppers, eggplantTransplant · May 28 – Jun 11

BeansSow outdoors · May 21 – Jun 4

Sweet cornSow outdoors · May 21 – Jun 4

Cucumbers, squashSow outdoors · May 21 – Jun 4

Fall lettuce, spinachSow outdoors · Aug 5 – Aug 19

GarlicPlant cloves · Sep 16 – Oct 21

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 14) and first fall frost (Sep 30) 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 84635 came on Mar 9 — 16 days earlier than the 1991–2020 average (Mar 25).

average
Mar 252026
Mar 9

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 6a in Utah

546 plants native to the lower 48 states, recorded in Utah, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. 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 Hinckley, UT.

Soil in Hinckley, UT

The soil mapped at the center of ZIP 84635 is Penoyer — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH8.8alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.5%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Penoyer silt loam, strongly saline.

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 84635; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hinckley, UT

Summer high95 °Faverage high, July

Winter low16 °Faverage low, January

Hot days76days a year at 90 °F or more

Freezing nights171nights a year at 32 °F or less

Growing degree days3,071base 50 °F — the season’s usable heat

Longest day14 h 57 mindaylight on June 21

Shortest day9 h 23 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation8.3 inper year, rain and melted snow

Snowfall20 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Deseret, UT (8 mi away); precipitation: Deseret, UT (8 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Leamington, UT · 26 mi

Utah planting zones →

Questions about 84635

What planting zone is ZIP code 84635?

ZIP code 84635 (Hinckley, UT) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Hinckley, UT?

The median last spring frost (32 °F) near 84635 is May 14; after May 31 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Deseret station.

When is the first frost in Hinckley, UT?

The median first fall frost near 84635 is September 30, giving a median frost-free growing season of 137 days.

When should I plant tomatoes in 84635?

Start tomato seeds indoors around Mar 19 – Apr 2 and set transplants outside around May 21 – Jun 4, one to three weeks after the median last frost.

How much rain and snow does 84635 get?

About 8.3 inches of precipitation a year and 20 inches of snowfall (NOAA 1991–2020 normals, Deseret station).

How hot do summers get in Hinckley, UT?

The average high peaks at 95 °F in July, with about 76 days a year at 90 °F or more.

What kind of soil does 84635 have?

The USDA soil survey maps Penoyer at the center of ZIP 84635: silt loam, well drained, pH about 8.8 (alkaline).

Did spring come early in Hinckley, UT in 2026?

Spring leaf-out near 84635 came on Mar 9 in 2026, 16 days earlier than the 1991–2020 average (Mar 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hinckley, UT?

Intermediate onions: the longest day near 84635 is 14 h 57 min, so day-neutral types bulb best; long-day varieties may not bulb fully.