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

Planting zone for Vernal, UT

Vernal, UT is in USDA zones 5b to 6a across its 2 ZIP codes. The median last spring frost is May 6 and the first fall frost October 7.

Vernal on the zone map

Outlined: its 1 ZIP code areas · 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.

Zones5b–6a−15 to −5 °F

ZIP codes2

Last frostMay 6

First frostOct 7

Growing season153 days

5b 1 ZIP 6a 1 ZIP

Frost forecast — next 7 nights

live from the National Weather Service

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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 Vernal, UT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 6median — 50% chance of a later frost

Safe for tender plantsMay 25only 10% chance of frost after

First fall frostOctober 7median — 10% chance by Sep 25

Growing season153 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 23 and returns around October 19.

From the NOAA station Vernal Municipal Airport, UT, elevation 5,259 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 Vernal

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 25 – Apr 8

SpinachSow outdoors · Mar 25 – Apr 15

Broccoli, cabbageStart indoors · Feb 25 – Mar 11

Broccoli, cabbageTransplant · Apr 15 – Apr 29

Onion setsPlant outdoors · Apr 8 – Apr 22

PotatoesPlant outdoors · Apr 15 – Apr 29

LettuceSow outdoors · Apr 8 – Apr 22

Carrots, beetsSow outdoors · Apr 15 – Apr 29

TomatoesStart indoors · Mar 11 – Mar 25

TomatoesTransplant · May 13 – May 27

Peppers, eggplantStart indoors · Feb 25 – Mar 11

Peppers, eggplantTransplant · May 20 – Jun 3

BeansSow outdoors · May 13 – May 27

Sweet cornSow outdoors · May 13 – May 27

Cucumbers, squashSow outdoors · May 13 – May 27

Fall lettuce, spinachSow outdoors · Aug 12 – Aug 26

GarlicPlant cloves · Sep 23 – Oct 28

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 6) and first fall frost (Oct 7) 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 84078 came on Mar 20 — 17 days earlier than the 1991–2020 average (Apr 6).

average
Apr 62026
Mar 20

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 5b in Utah

517 plants native to the lower 48 states, recorded in Utah, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. 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 Vernal, UT.

Soil in Vernal, UT

The soil mapped at the center of ZIP 84078 is Nolava — loam, well drained.

TextureLoama good balance for most vegetables

pH8.5alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Nolava loam, 4 to 8 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 84078; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Vernal, UT

Summer high91 °Faverage high, July

Winter low10 °Faverage low, January

Hot days42days a year at 90 °F or more

Freezing nights173nights a year at 32 °F or less

Growing degree days2,693base 50 °F — the season’s usable heat

Longest day15 h 04 mindaylight on June 21

Shortest day9 h 17 mindaylight on December 21

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

Precipitation8.6 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: Vernal Municipal Airport, UT (2 mi away); precipitation: Vernal Municipal Airport, UT (2 mi away). Daylight is calculated from latitude.

ZIP codes in Vernal

Utah planting zones →

Questions about Vernal

What planting zone is Vernal, UT?

Vernal, UT is in USDA hardiness zones 5b to 6a on the 2023 map (5b: −15 to −10 °F; 6a: −10 to −5 °F).

When is the last frost in Vernal, UT?

The median last spring frost is May 6 and the median first fall frost is October 7 (NOAA 1991–2020 normals, Vernal Municipal Airport station).

When can I plant a garden in Vernal, UT?

Cool-season crops like peas and spinach go in around Mar 25 – Apr 15; tomatoes, peppers, beans and squash after about May 13, once frost risk has passed.

What kind of onions grow in Vernal, UT?

Long-day onions: the longest day is 15 h 04 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Vernal, UT get?

About 8.6 inches of precipitation a year (NOAA 1991–2020 normals).