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

Planting zone for 84716 — Boulder, UT

ZIP code 84716 (Boulder, Garfield County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 4 and the first fall frost October 14.

Where ZIP 84716 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.

Zone7a0 to 5 °F

Coldest night−17.8 to −15 °C

Last frostMay 4

First frostOct 14

2012 zone7a

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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Boulder, 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 Boulder, UT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 4median — 50% chance of a later frost

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

First fall frostOctober 14median — 10% chance by Sep 30

Growing season160 daysfrost-free, median

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

From the NOAA station Boulder, UT — 3 miles away, elevation 6,651 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 84716

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 23 – Apr 6

SpinachSow outdoors · Mar 23 – Apr 13

Broccoli, cabbageStart indoors · Feb 23 – Mar 9

Broccoli, cabbageTransplant · Apr 13 – Apr 27

Onion setsPlant outdoors · Apr 6 – Apr 20

PotatoesPlant outdoors · Apr 13 – Apr 27

LettuceSow outdoors · Apr 6 – Apr 20

Carrots, beetsSow outdoors · Apr 13 – Apr 27

TomatoesStart indoors · Mar 9 – Mar 23

TomatoesTransplant · May 11 – May 25

Peppers, eggplantStart indoors · Feb 23 – Mar 9

Peppers, eggplantTransplant · May 18 – Jun 1

BeansSow outdoors · May 11 – May 25

Sweet cornSow outdoors · May 11 – May 25

Cucumbers, squashSow outdoors · May 11 – May 25

Fall lettuce, spinachSow outdoors · Aug 19 – Sep 2

GarlicPlant cloves · Sep 30 – Nov 4

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 4) and first fall frost (Oct 14) 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 84716 came on Mar 11 — 32 days earlier than the 1991–2020 average (Apr 12).

average
Apr 122026
Mar 11

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 7a in Utah

561 plants native to the lower 48 states, recorded in Utah, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 Boulder, UT.

Soil in Boulder, UT

The soil mapped at the center of ZIP 84716 is Notlic family — very gravelly loam, well drained.

TextureVery gravelly loama good balance for most vegetables

pH8.0alkaline; 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: Notlic family-Cragola family-Atchee family complex, moist, 20 to 50 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 84716; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Boulder, UT

Summer high84 °Faverage high, July

Winter low21 °Faverage low, January

Hot days8days a year at 90 °F or more

Freezing nights146nights a year at 32 °F or less

Growing degree days2,651base 50 °F — the season’s usable heat

Longest day14 h 48 mindaylight on June 21

Shortest day9 h 32 mindaylight on December 21

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

Precipitation11.8 inper year, rain and melted snow

Snowfall52 inper year; 37 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Boulder, UT (3 mi away); precipitation: Boulder, UT (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

847267a

Escalante, UT · 15 mi

847736a

Teasdale, UT · 21 mi

847366b

Henrieville, UT · 27 mi

Utah planting zones →

Questions about 84716

What planting zone is ZIP code 84716?

ZIP code 84716 (Boulder, UT) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Boulder, UT?

The median last spring frost (32 °F) near 84716 is May 4; after May 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Boulder station.

When is the first frost in Boulder, UT?

The median first fall frost near 84716 is October 14, giving a median frost-free growing season of 160 days.

When should I plant tomatoes in 84716?

Start tomato seeds indoors around Mar 9 – Mar 23 and set transplants outside around May 11 – May 25, one to three weeks after the median last frost.

How much rain and snow does 84716 get?

About 11.8 inches of precipitation a year and 52 inches of snowfall (NOAA 1991–2020 normals, Boulder station).

How hot do summers get in Boulder, UT?

The average high peaks at 84 °F in July, with about 8 days a year at 90 °F or more.

What kind of soil does 84716 have?

The USDA soil survey maps Notlic family at the center of ZIP 84716: very gravelly loam, well drained, pH about 8.0 (alkaline).

Did spring come early in Boulder, UT in 2026?

Spring leaf-out near 84716 came on Mar 11 in 2026, 32 days earlier than the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Boulder, UT?

Intermediate onions: the longest day near 84716 is 14 h 48 min, so day-neutral types bulb best; long-day varieties may not bulb fully.