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

Planting zone for 84329 — Park Valley, UT

ZIP code 84329 (Park Valley, Box Elder County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 21 and the first fall frost October 2.

Where ZIP 84329 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 21

First frostOct 2

2012 zone6b

Was 6b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Park Valley, 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 Park Valley, UT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 21median — 50% chance of a later frost

Safe for tender plantsJune 11only 10% chance of frost after

First fall frostOctober 2median — 10% chance by Sep 17

Growing season132 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 3 and returns around October 12.

From the NOAA station Rosette, UT — 3 miles away, elevation 5,686 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 84329

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 9 – Apr 23

SpinachSow outdoors · Apr 9 – Apr 30

Broccoli, cabbageStart indoors · Mar 12 – Mar 26

Broccoli, cabbageTransplant · Apr 30 – May 14

Onion setsPlant outdoors · Apr 23 – May 7

PotatoesPlant outdoors · Apr 30 – May 14

LettuceSow outdoors · Apr 23 – May 7

Carrots, beetsSow outdoors · Apr 30 – May 14

TomatoesStart indoors · Mar 26 – Apr 9

TomatoesTransplant · May 28 – Jun 11

Peppers, eggplantStart indoors · Mar 12 – Mar 26

Peppers, eggplantTransplant · Jun 4 – Jun 18

BeansSow outdoors · May 28 – Jun 11

Sweet cornSow outdoors · May 28 – Jun 11

Cucumbers, squashSow outdoors · May 28 – Jun 11

Fall lettuce, spinachSow outdoors · Aug 7 – Aug 21

GarlicPlant cloves · Sep 18 – Oct 23

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 21) and first fall frost (Oct 2) 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 84329 came on Mar 23 — 17 days earlier than the 1991–2020 average (Apr 9).

average
Apr 92026
Mar 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 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 Park Valley, UT.

Soil in Park Valley, UT

The soil mapped at the center of ZIP 84329 is Lembos — loam, well drained.

TextureLoama good balance for most vegetables

pH8.5alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classFarmland of local importanceUSDA classification

Map unit: Lembos-Taylorsflat complex, 1 to 6 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 84329; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Park Valley, UT

Summer high86 °Faverage high, July

Winter low16 °Faverage low, January

Hot days22days a year at 90 °F or more

Freezing nights175nights a year at 32 °F or less

Growing degree days2,343base 50 °F — the season’s usable heat

Longest day15 h 13 mindaylight on June 21

Shortest day9 h 08 mindaylight on December 21

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

Precipitation11.9 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: Rosette, UT (3 mi away); precipitation: Rosette, UT (3 mi away). 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.

Grouse Creek, UT · 32 mi

843366a

Snowville, UT · 32 mi

Utah planting zones →

Questions about 84329

What planting zone is ZIP code 84329?

ZIP code 84329 (Park Valley, 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 Park Valley, UT?

The median last spring frost (32 °F) near 84329 is May 21; after June 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Rosette station.

When is the first frost in Park Valley, UT?

The median first fall frost near 84329 is October 2, giving a median frost-free growing season of 132 days.

When should I plant tomatoes in 84329?

Start tomato seeds indoors around Mar 26 – Apr 9 and set transplants outside around May 28 – Jun 11, one to three weeks after the median last frost.

How much rain and snow does 84329 get?

About 11.9 inches of precipitation a year (NOAA 1991–2020 normals, Rosette station).

How hot do summers get in Park Valley, UT?

The average high peaks at 86 °F in July, with about 22 days a year at 90 °F or more.

What kind of soil does 84329 have?

The USDA soil survey maps Lembos at the center of ZIP 84329: loam, well drained, pH about 8.5 (alkaline).

Did spring come early in Park Valley, UT in 2026?

Spring leaf-out near 84329 came on Mar 23 in 2026, 17 days earlier than the 1991–2020 average (Apr 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Park Valley, UT?

Long-day onions: the longest day near 84329 is 15 h 13 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 84329 change?

Yes. The 2012 USDA map put 84329 in zone 6b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.