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

Planting zone for 80238 — Denver, CO

ZIP code 80238 (Denver, Denver County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 4 and the first fall frost October 8.

Where ZIP 80238 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 4

First frostOct 8

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 Denver, CO…

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 Denver, CO

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 16only 10% chance of frost after

First fall frostOctober 8median — 10% chance by Sep 25

Growing season156 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 22 and returns around October 18.

From the NOAA station Denver-Stapleton, CO — within 1 mile, elevation 5,286 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 80238

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 13 – Aug 27

GarlicPlant cloves · Sep 24 – Oct 29

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 4) and first fall frost (Oct 8) 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 80238 came on Feb 19 — 28 days earlier than the 1991–2020 average (Mar 19).

average
Mar 192026
Feb 19

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 Colorado

563 plants native to the lower 48 states, recorded in Colorado, 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 Denver, CO.

Soil in Denver, CO

The soil mapped at the center of ZIP 80238 is Elyria — loam, well drained.

TextureLoama good balance for most vegetables

pH7.4slightly alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Elyria-Urban land-Racas complex, 3 to 5 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 80238; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Denver, CO

Summer high90 °Faverage high, July

Winter low18 °Faverage low, January

Hot days42days a year at 90 °F or more

Freezing nights156nights a year at 32 °F or less

Growing degree days3,011base 50 °F — the season’s usable heat

Longest day14 h 59 mindaylight on June 21

Shortest day9 h 21 mindaylight on December 21

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

Precipitation15.4 inper year, rain and melted snow

Snowfall49 inper year; 43 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: Denver-Stapleton, CO (within 1 mile); precipitation: Denver-Stapleton, CO (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

Commerce City, CO · 4 mi

All 59 ZIP codes in Denver → · Colorado planting zones →

Questions about 80238

What planting zone is ZIP code 80238?

ZIP code 80238 (Denver, CO) 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 Denver, CO?

The median last spring frost (32 °F) near 80238 is May 4; after May 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Denver-Stapleton station.

When is the first frost in Denver, CO?

The median first fall frost near 80238 is October 8, giving a median frost-free growing season of 156 days.

When should I plant tomatoes in 80238?

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 80238 get?

About 15.4 inches of precipitation a year and 49 inches of snowfall (NOAA 1991–2020 normals, Denver-Stapleton station).

How hot do summers get in Denver, CO?

The average high peaks at 90 °F in July, with about 42 days a year at 90 °F or more.

What kind of soil does 80238 have?

The USDA soil survey maps Elyria at the center of ZIP 80238: loam, well drained, pH about 7.4 (slightly alkaline).

Did spring come early in Denver, CO in 2026?

Spring leaf-out near 80238 came on Feb 19 in 2026, 28 days earlier than the 1991–2020 average (Mar 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Denver, CO?

Intermediate onions: the longest day near 80238 is 14 h 59 min, so day-neutral types bulb best; long-day varieties may not bulb fully.