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

Planting zone for 80103 — Byers, CO

ZIP code 80103 (Byers, Arapahoe County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 13 and the first fall frost October 2.

Where ZIP 80103 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.

Zone5b−15 to −10 °F
Coldest night−26.1 to −23.3 °C
Last frostMay 13
First frostOct 2
2012 zone5a

Was 5a 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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Byers, 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 Byers, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 13median — 50% chance of a later frost
Safe for tender plantsMay 30only 10% chance of frost after
First fall frostOctober 2median — 10% chance by Sep 20
Growing season142 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 2 and returns around October 10.

From the NOAA station Byers 5 Ene, CO — 4 miles away, elevation 5,102 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 80103

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 1 – Apr 15
SpinachSow outdoors · Apr 1 – Apr 22
Broccoli, cabbageStart indoors · Mar 4 – Mar 18
Broccoli, cabbageTransplant · Apr 22 – May 6
Onion setsPlant outdoors · Apr 15 – Apr 29
PotatoesPlant outdoors · Apr 22 – May 6
LettuceSow outdoors · Apr 15 – Apr 29
Carrots, beetsSow outdoors · Apr 22 – May 6
TomatoesStart indoors · Mar 18 – Apr 1
TomatoesTransplant · May 20 – Jun 3
Peppers, eggplantStart indoors · Mar 4 – Mar 18
Peppers, eggplantTransplant · May 27 – Jun 10
BeansSow outdoors · May 20 – Jun 3
Sweet cornSow outdoors · May 20 – Jun 3
Cucumbers, squashSow outdoors · May 20 – Jun 3
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 13) 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 80103 came on Mar 1 — 25 days earlier than the 1991–2020 average (Mar 26).

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 Colorado

546 plants native to the lower 48 states, recorded in Colorado, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. Each links to its USDA PLANTS profile.

Trees 27

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 98

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 246

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 163

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 3

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °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 Byers, CO.

Soil in Byers, CO

The soil mapped at the center of ZIP 80103 is Ascalon — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH7.0neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Ascalon-Vona sandy loams, 1 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 80103; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Byers, CO

Summer high90 °Faverage high, July
Winter low14 °Faverage low, January
Hot days48days a year at 90 °F or more
Freezing nights176nights a year at 32 °F or less
Growing degree days2,725base 50 °F — the season’s usable heat
Longest day15 h 00 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
Precipitation16.3 inper year, rain and melted snow
Snowfall43 inper year; 48 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 42 °F, low 14 °F 42°14° JanFebruary: average high 45 °F, low 16 °F 45°16° FebMarch: average high 54 °F, low 25 °F 54°25° MarApril: average high 61 °F, low 32 °F 61°32° AprMay: average high 71 °F, low 42 °F 71°42° MayJune: average high 83 °F, low 51 °F 83°51° JunJuly: average high 90 °F, low 57 °F 90°57° JulAugust: average high 87 °F, low 56 °F 87°56° AugSeptember: average high 79 °F, low 47 °F 79°47° SepOctober: average high 65 °F, low 33 °F 65°33° OctNovember: average high 53 °F, low 22 °F 53°22° NovDecember: average high 43 °F, low 14 °F 43°14° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″January: 0.45 in precipitation, 6.1 in snowfall 0.5❄6 JanFebruary: 0.52 in precipitation, 6.3 in snowfall 0.5❄6 FebMarch: 1.21 in precipitation, 7.3 in snowfall 1.2❄7 MarApril: 1.82 in precipitation, 5.5 in snowfall 1.8❄6 AprMay: 2.46 in precipitation, 0.7 in snowfall 2.5❄1 MayJune: 1.98 in precipitation 2.0 JunJuly: 2.56 in precipitation 2.6 JulAugust: 1.99 in precipitation 2.0 AugSeptember: 1.20 in precipitation, 0.9 in snowfall 1.2❄1 SepOctober: 0.98 in precipitation, 3.8 in snowfall 1.0❄4 OctNovember: 0.67 in precipitation, 5.9 in snowfall 0.7❄6 NovDecember: 0.45 in precipitation, 6.2 in snowfall 0.5❄6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Byers 5 Ene, CO (4 mi away); precipitation: Byers 5 Ene, CO (4 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.

801365b
Strasburg, CO · 10 mi
801055b
Deer Trail, CO · 13 mi
800416a
Aurora, CO · 17 mi
800446a
Aurora, CO · 17 mi
800466a
Aurora, CO · 17 mi
800476a
Aurora, CO · 17 mi
801026a
Bennett, CO · 19 mi
806545a
Wiggins, CO · 24 mi

Colorado planting zones →

Questions about 80103

What planting zone is ZIP code 80103?

ZIP code 80103 (Byers, CO) is in USDA hardiness zone 5b on the 2023 map: the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C).

When is the last frost in Byers, CO?

The median last spring frost (32 °F) near 80103 is May 13; after May 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Byers 5 Ene station.

When is the first frost in Byers, CO?

The median first fall frost near 80103 is October 2, giving a median frost-free growing season of 142 days.

When should I plant tomatoes in 80103?

Start tomato seeds indoors around Mar 18 – Apr 1 and set transplants outside around May 20 – Jun 3, one to three weeks after the median last frost.

How much rain and snow does 80103 get?

About 16.3 inches of precipitation a year and 43 inches of snowfall (NOAA 1991–2020 normals, Byers 5 Ene station).

How hot do summers get in Byers, CO?

The average high peaks at 90 °F in July, with about 48 days a year at 90 °F or more.

What kind of soil does 80103 have?

The USDA soil survey maps Ascalon at the center of ZIP 80103: sandy loam, well drained, pH about 7.0 (neutral).

Did spring come early in Byers, CO in 2026?

Spring leaf-out near 80103 came on Mar 1 in 2026, 25 days earlier than the 1991–2020 average (Mar 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Byers, CO?

Intermediate onions: the longest day near 80103 is 15 h 00 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 80103 change?

Yes. The 2012 USDA map put 80103 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.