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

Planting zone for 80018 — Aurora, CO

ZIP code 80018 (Aurora, Arapahoe County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 5 and the first fall frost October 9.

Where ZIP 80018 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 5
First frostOct 9
2012 zone5b

Was 5b on the 2012 map — half a zone warmer 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 Aurora, 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 Aurora, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 5median — 50% chance of a later frost
Safe for tender plantsMay 19only 10% chance of frost after
First fall frostOctober 9median — 10% chance by Sep 27
Growing season156 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 25 and returns around October 18.

From the NOAA station Denver Intl Airport, CO — 9 miles away, elevation 5,414 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 80018

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 24 – Apr 7
SpinachSow outdoors · Mar 24 – Apr 14
Broccoli, cabbageStart indoors · Feb 24 – Mar 10
Broccoli, cabbageTransplant · Apr 14 – Apr 28
Onion setsPlant outdoors · Apr 7 – Apr 21
PotatoesPlant outdoors · Apr 14 – Apr 28
LettuceSow outdoors · Apr 7 – Apr 21
Carrots, beetsSow outdoors · Apr 14 – Apr 28
TomatoesStart indoors · Mar 10 – Mar 24
TomatoesTransplant · May 12 – May 26
Peppers, eggplantStart indoors · Feb 24 – Mar 10
Peppers, eggplantTransplant · May 19 – Jun 2
BeansSow outdoors · May 12 – May 26
Sweet cornSow outdoors · May 12 – May 26
Cucumbers, squashSow outdoors · May 12 – May 26
Fall lettuce, spinachSow outdoors · Aug 14 – Aug 28
GarlicPlant cloves · Sep 25 – Oct 30
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 5) and first fall frost (Oct 9) 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 80018 came on Feb 20 — 29 days earlier than the 1991–2020 average (Mar 21).

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.

Trees 28

American elm120 ft · blooms early spring · medium shade tolerance · to −46 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fblack walnut100 ft · blooms late spring · high shade tolerance · to −28 °Fblack willow100 ft · blooms early spring · high shade tolerance · to −58 °Fblue spruce100 ft · blooms late spring · medium shade tolerance · to −38 °F

Shrubs 104

alderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FApache plume6 ft · blooms late spring · high shade tolerance · to −23 °F

Wildflowers & perennials 251

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine aster0.3 ft · blooms early summer · medium shade tolerance · to −28 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °F

Grasses 167

Alaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °Falkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °FAlpine Meadow-Foxtail0.5 ft · blooms mid spring · medium shade tolerance · to −33 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °Fanalogue sedge1.5 ft · blooms late spring · medium shade tolerance · to −38 °F

Vines 4

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °FVirginia creeper1 ft · blooms late spring · medium shade tolerance · to −28 °Fwestern white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

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 Aurora, CO.

Soil in Aurora, CO

The soil mapped at the center of ZIP 80018 is Bresser — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH6.7neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Bresser-Truckton sandy loams, 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 80018; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Aurora, CO

Summer high90 °Faverage high, July
Winter low18 °Faverage low, December
Hot days46days a year at 90 °F or more
Freezing nights156nights a year at 32 °F or less
Growing degree days3,044base 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
Precipitation17.5 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 45 °F, low 19 °F 45°19° JanFebruary: average high 46 °F, low 20 °F 46°20° FebMarch: average high 56 °F, low 28 °F 56°28° MarApril: average high 62 °F, low 34 °F 62°34° AprMay: average high 71 °F, low 44 °F 71°44° MayJune: average high 83 °F, low 53 °F 83°53° JunJuly: average high 90 °F, low 60 °F 90°60° JulAugust: average high 88 °F, low 58 °F 88°58° AugSeptember: average high 80 °F, low 50 °F 80°50° SepOctober: average high 65 °F, low 37 °F 65°37° OctNovember: average high 53 °F, low 26 °F 53°26° NovDecember: average high 44 °F, low 18 °F 44°18° Dec

Precipitation by month inches

0″1″2″3″January: 0.58 in precipitation 0.6 JanFebruary: 0.64 in precipitation 0.6 FebMarch: 1.83 in precipitation 1.8 MarApril: 2.16 in precipitation 2.2 AprMay: 2.26 in precipitation 2.3 MayJune: 1.93 in precipitation 1.9 JunJuly: 2.17 in precipitation 2.2 JulAugust: 2.05 in precipitation 2.0 AugSeptember: 1.38 in precipitation 1.4 SepOctober: 1.20 in precipitation 1.2 OctNovember: 0.78 in precipitation 0.8 NovDecember: 0.56 in precipitation 0.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Denver Intl Airport, CO (9 mi away); precipitation: Aurora 2.1 Ese, CO (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

800176a
Aurora, CO · 5 mi
801376a
Watkins, CO · 5 mi
800136a
Aurora, CO · 5 mi
800196a
Aurora, CO · 5 mi
800116a
Aurora, CO · 6 mi
800156a
Aurora, CO · 8 mi
800166a
Aurora, CO · 8 mi
800406a
Aurora, CO · 8 mi

All 17 ZIP codes in Aurora → · Colorado planting zones →

Questions about 80018

What planting zone is ZIP code 80018?

ZIP code 80018 (Aurora, 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 Aurora, CO?

The median last spring frost (32 °F) near 80018 is May 5; after May 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Denver Intl Airport station.

When is the first frost in Aurora, CO?

The median first fall frost near 80018 is October 9, giving a median frost-free growing season of 156 days.

When should I plant tomatoes in 80018?

Start tomato seeds indoors around Mar 10 – Mar 24 and set transplants outside around May 12 – May 26, one to three weeks after the median last frost.

How much rain and snow does 80018 get?

About 17.5 inches of precipitation a year (NOAA 1991–2020 normals, Aurora 2.1 Ese station).

How hot do summers get in Aurora, CO?

The average high peaks at 90 °F in July, with about 46 days a year at 90 °F or more.

What kind of soil does 80018 have?

The USDA soil survey maps Bresser at the center of ZIP 80018: sandy loam, well drained, pH about 6.7 (neutral).

Did spring come early in Aurora, CO in 2026?

Spring leaf-out near 80018 came on Feb 20 in 2026, 29 days earlier than the 1991–2020 average (Mar 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Aurora, CO?

Intermediate onions: the longest day near 80018 is 14 h 59 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 80018 change?

Yes. The 2012 USDA map put 80018 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.