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

Planting zone for 84710 — Alton, UT

ZIP code 84710 (Alton, Kane County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is June 1 and the first fall frost September 30.

Where ZIP 84710 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 frostJun 1

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 Alton, 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 Alton, UT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 1median — 50% chance of a later frost

Safe for tender plantsJune 15only 10% chance of frost after

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

Growing season120 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 17 and returns around October 11.

From the NOAA station Alton, UT — 2 miles away, elevation 7,100 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 84710

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 20 – May 4

SpinachSow outdoors · Apr 20 – May 11

Broccoli, cabbageStart indoors · Mar 23 – Apr 6

Broccoli, cabbageTransplant · May 11 – May 25

Onion setsPlant outdoors · May 4 – May 18

PotatoesPlant outdoors · May 11 – May 25

LettuceSow outdoors · May 4 – May 18

Carrots, beetsSow outdoors · May 11 – May 25

TomatoesStart indoors · Apr 6 – Apr 20

TomatoesTransplant · Jun 8 – Jun 22

Peppers, eggplantStart indoors · Mar 23 – Apr 6

Peppers, eggplantTransplant · Jun 15 – Jun 29

BeansSow outdoors · Jun 8 – Jun 22

Sweet cornSow outdoors · Jun 8 – Jun 22

Cucumbers, squashSow outdoors · Jun 8 – Jun 22

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 (Jun 1) 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 84710 came on Mar 17 — 27 days earlier than the 1991–2020 average (Apr 13).

average
Apr 132026
Mar 17

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 Alton, UT.

Soil in Alton, UT

The soil mapped at the center of ZIP 84710 is Diagulch — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter75%high

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Diagulch-Ess-Longvalley complex, 8 to 35 percent slopes.

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 84710; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Alton, UT

Summer high85 °Faverage high, July

Winter low18 °Faverage low, January

Hot days12days a year at 90 °F or more

Freezing nights190nights a year at 32 °F or less

Growing degree days1,945base 50 °F — the season’s usable heat

Longest day14 h 45 mindaylight on June 21

Shortest day9 h 34 mindaylight on December 21

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

Precipitation20.2 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: Alton, UT (2 mi away); precipitation: Long Valley Jct, UT (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

847296b

Glendale, UT · 10 mi

847626a

Duck Creek Village, UT · 13 mi

847356a

Hatch, UT · 13 mi

847586b

Orderville, UT · 18 mi

847196a

Brian Head, UT · 20 mi

847557a

Mount Carmel, UT · 23 mi

847417a

Kanab, UT · 24 mi

847186a

Cannonville, UT · 25 mi

Utah planting zones →

Questions about 84710

What planting zone is ZIP code 84710?

ZIP code 84710 (Alton, 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 Alton, UT?

The median last spring frost (32 °F) near 84710 is June 1; after June 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Alton station.

When is the first frost in Alton, UT?

The median first fall frost near 84710 is September 30, giving a median frost-free growing season of 120 days.

When should I plant tomatoes in 84710?

Start tomato seeds indoors around Apr 6 – Apr 20 and set transplants outside around Jun 8 – Jun 22, one to three weeks after the median last frost.

How much rain and snow does 84710 get?

About 20.2 inches of precipitation a year (NOAA 1991–2020 normals, Long Valley Jct station).

How hot do summers get in Alton, UT?

The average high peaks at 85 °F in July, with about 12 days a year at 90 °F or more.

What kind of soil does 84710 have?

The USDA soil survey maps Diagulch at the center of ZIP 84710: slightly decomposed plant material, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Alton, UT in 2026?

Spring leaf-out near 84710 came on Mar 17 in 2026, 27 days earlier than the 1991–2020 average (Apr 13), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Alton, UT?

Intermediate onions: the longest day near 84710 is 14 h 45 min, so day-neutral types bulb best; long-day varieties may not bulb fully.