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

Planting zone for 81236 — Nathrop, CO

ZIP code 81236 (Nathrop, Chaffee County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 27 and the first fall frost September 23.

Where ZIP 81236 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 27

First frostSep 23

2012 zone6a

Was 6a on the 2012 map — half a zone colder 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 Nathrop, 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 Nathrop, CO

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 27median — 50% chance of a later frost

Safe for tender plantsJune 11only 10% chance of frost after

First fall frostSeptember 23median — 10% chance by Sep 10

Growing season116 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 15 and returns around October 2.

From the NOAA station Buena Vista 2s, CO — 12 miles away, elevation 7,953 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 81236

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 15 – Apr 29

SpinachSow outdoors · Apr 15 – May 6

Broccoli, cabbageStart indoors · Mar 18 – Apr 1

Broccoli, cabbageTransplant · May 6 – May 20

Onion setsPlant outdoors · Apr 29 – May 13

PotatoesPlant outdoors · May 6 – May 20

LettuceSow outdoors · Apr 29 – May 13

Carrots, beetsSow outdoors · May 6 – May 20

TomatoesStart indoors · Apr 1 – Apr 15

TomatoesTransplant · Jun 3 – Jun 17

Peppers, eggplantStart indoors · Mar 18 – Apr 1

Peppers, eggplantTransplant · Jun 10 – Jun 24

BeansSow outdoors · Jun 3 – Jun 17

Sweet cornSow outdoors · Jun 3 – Jun 17

Cucumbers, squashSow outdoors · Jun 3 – Jun 17

Fall lettuce, spinachSow outdoors · Jul 29 – Aug 12

GarlicPlant cloves · Sep 9 – Oct 14

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 27) and first fall frost (Sep 23) 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 81236 came on May 28 — 12 days earlier than the 1991–2020 average (Jun 9).

average
Jun 92026
May 28

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.

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 Nathrop, CO.

Soil in Nathrop, CO

The soil mapped at the center of ZIP 81236 is Leighcan family — slightly decomposed plant material, somewhat excessively drained.

TextureSlightly decomposed plant materialtop layer

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter75%high

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Leighcan-Endlich families complex, 40 to 60 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 81236; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Nathrop, CO

Summer high83 °Faverage high, July

Winter low11 °Faverage low, January

Hot days5days a year at 90 °F or more

Freezing nights208nights a year at 32 °F or less

Growing degree days1,641base 50 °F — the season’s usable heat

Longest day14 h 52 mindaylight on June 21

Shortest day9 h 27 mindaylight on December 21

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

Precipitation24.7 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Buena Vista 2s, CO (12 mi away); precipitation: Saint Elmo, CO (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Poncha Springs, CO · 17 mi

812375a

Ohio City, CO · 20 mi

812394b

Parlin, CO · 21 mi

812115b

Buena Vista, CO · 21 mi

812485b

Sargents, CO · 22 mi

Colorado planting zones →

Questions about 81236

What planting zone is ZIP code 81236?

ZIP code 81236 (Nathrop, 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 Nathrop, CO?

The median last spring frost (32 °F) near 81236 is May 27; after June 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Buena Vista 2s station.

When is the first frost in Nathrop, CO?

The median first fall frost near 81236 is September 23, giving a median frost-free growing season of 116 days.

When should I plant tomatoes in 81236?

Start tomato seeds indoors around Apr 1 – Apr 15 and set transplants outside around Jun 3 – Jun 17, one to three weeks after the median last frost.

How much rain and snow does 81236 get?

About 24.7 inches of precipitation a year (NOAA 1991–2020 normals, Saint Elmo station).

How hot do summers get in Nathrop, CO?

The average high peaks at 83 °F in July, with about 5 days a year at 90 °F or more.

What kind of soil does 81236 have?

The USDA soil survey maps Leighcan family at the center of ZIP 81236: slightly decomposed plant material, somewhat excessively drained, pH about 5.0 (strongly acidic).

Did spring come early in Nathrop, CO in 2026?

Spring leaf-out near 81236 came on May 28 in 2026, 12 days earlier than the 1991–2020 average (Jun 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Nathrop, CO?

Intermediate onions: the longest day near 81236 is 14 h 52 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 81236 change?

Yes. The 2012 USDA map put 81236 in zone 6a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.