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

Planting zone for 81639 — Hayden, CO

ZIP code 81639 (Hayden, Routt County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is June 1 and the first fall frost September 20.

Where ZIP 81639 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.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostJun 1

First frostSep 20

2012 zone4b

Was 4b 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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Hayden, 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 Hayden, CO

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 1median — 50% chance of a later frost

Safe for tender plantsJune 16only 10% chance of frost after

First fall frostSeptember 20median — 10% chance by Sep 7

Growing season109 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 13 and returns around September 29.

From the NOAA station Hayden, CO — 5 miles away, elevation 6,467 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 81639

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 20 – May 4

SpinachSow outdoors · Apr 20 – May 11

Broccoli, cabbageStart indoors · Mar 23 – Apr 6

Broccoli, cabbageTransplant · May 11 – May 25

Onion setsPlant outdoors · May 4 – May 18

PotatoesPlant outdoors · May 11 – May 25

LettuceSow outdoors · May 4 – May 18

Carrots, beetsSow outdoors · May 11 – May 25

TomatoesStart indoors · Apr 6 – Apr 20

TomatoesTransplant · Jun 8 – Jun 22

Peppers, eggplantStart indoors · Mar 23 – Apr 6

Peppers, eggplantTransplant · Jun 15 – Jun 29

BeansSow outdoors · Jun 8 – Jun 22

Sweet cornSow outdoors · Jun 8 – Jun 22

Cucumbers, squashSow outdoors · Jun 8 – Jun 22

Fall lettuce, spinachSow outdoors · Jul 26 – Aug 9

GarlicPlant cloves · Sep 6 – Oct 11

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 1) and first fall frost (Sep 20) 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 81639 came on Mar 29 — 26 days earlier than the 1991–2020 average (Apr 24).

average
Apr 242026
Mar 29

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).

Soil in Hayden, CO

The soil mapped at the center of ZIP 81639 is Foidel — loam, well drained.

TextureLoama good balance for most vegetables

pH7.0neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter3.5%moderate

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Foidel loam, 25 to 65 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 81639; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hayden, CO

Summer high86 °Faverage high, July

Winter low8 °Faverage low, January

Hot days13days a year at 90 °F or more

Freezing nights197nights a year at 32 °F or less

Growing degree days1,831base 50 °F — the season’s usable heat

Longest day15 h 05 mindaylight on June 21

Shortest day9 h 16 mindaylight on December 21

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

Precipitation18.4 inper year, rain and melted snow

Snowfall113 inper year; 125 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: Hayden, CO (5 mi away); precipitation: Hayden, CO (5 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.

816264a

Craig, CO · 16 mi

804875b

Steamboat Springs, CO · 19 mi

804884b

Steamboat Springs, CO · 21 mi

804774b

Steamboat Springs, CO · 22 mi

Colorado planting zones →

Questions about 81639

What planting zone is ZIP code 81639?

ZIP code 81639 (Hayden, CO) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Hayden, CO?

The median last spring frost (32 °F) near 81639 is June 1; after June 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hayden station.

When is the first frost in Hayden, CO?

The median first fall frost near 81639 is September 20, giving a median frost-free growing season of 109 days.

When should I plant tomatoes in 81639?

Start tomato seeds indoors around Apr 6 – Apr 20 and set transplants outside around Jun 8 – Jun 22, one to three weeks after the median last frost.

How much rain and snow does 81639 get?

About 18.4 inches of precipitation a year and 113 inches of snowfall (NOAA 1991–2020 normals, Hayden station).

How hot do summers get in Hayden, CO?

The average high peaks at 86 °F in July, with about 13 days a year at 90 °F or more.

What kind of soil does 81639 have?

The USDA soil survey maps Foidel at the center of ZIP 81639: loam, well drained, pH about 7.0 (neutral).

Did spring come early in Hayden, CO in 2026?

Spring leaf-out near 81639 came on Mar 29 in 2026, 26 days earlier than the 1991–2020 average (Apr 24), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hayden, CO?

Long-day onions: the longest day near 81639 is 15 h 05 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 81639 change?

Yes. The 2012 USDA map put 81639 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.