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

Planting zone for 80736 — Iliff, CO

ZIP code 80736 (Iliff, Logan County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 11 and the first fall frost October 4.

Where ZIP 80736 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 11
First frostOct 4
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 Iliff, 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 Iliff, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 11median — 50% chance of a later frost
Safe for tender plantsMay 23only 10% chance of frost after
First fall frostOctober 4median — 10% chance by Sep 23
Growing season145 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 2 and returns around October 12.

From the NOAA station Crook, CO — 12 miles away, elevation 3,711 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 80736

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 30 – Apr 13
SpinachSow outdoors · Mar 30 – Apr 20
Broccoli, cabbageStart indoors · Mar 2 – Mar 16
Broccoli, cabbageTransplant · Apr 20 – May 4
Onion setsPlant outdoors · Apr 13 – Apr 27
PotatoesPlant outdoors · Apr 20 – May 4
LettuceSow outdoors · Apr 13 – Apr 27
Carrots, beetsSow outdoors · Apr 20 – May 4
TomatoesStart indoors · Mar 16 – Mar 30
TomatoesTransplant · May 18 – Jun 1
Peppers, eggplantStart indoors · Mar 2 – Mar 16
Peppers, eggplantTransplant · May 25 – Jun 8
BeansSow outdoors · May 18 – Jun 1
Sweet cornSow outdoors · May 18 – Jun 1
Cucumbers, squashSow outdoors · May 18 – Jun 1
Fall lettuce, spinachSow outdoors · Aug 9 – Aug 23
GarlicPlant cloves · Sep 20 – Oct 25
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 11) and first fall frost (Oct 4) 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 80736 came on Mar 1 — 24 days earlier than the 1991–2020 average (Mar 25).

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 Iliff, CO

The soil mapped at the center of ZIP 80736 is Wages — loam, well drained.

TextureLoama good balance for most vegetables
pH7.2neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Wages-Rosebud loams, 5 to 9 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 80736; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Iliff, CO

Summer high92 °Faverage high, July
Winter low13 °Faverage low, January
Hot days63days a year at 90 °F or more
Freezing nights178nights a year at 32 °F or less
Growing degree days3,013base 50 °F — the season’s usable heat
Longest day15 h 06 mindaylight on June 21
Shortest day9 h 14 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation16.9 inper year, rain and melted snow
Snowfall25 inper year; 30 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 44 °F, low 13 °F 44°13° JanFebruary: average high 47 °F, low 16 °F 47°16° FebMarch: average high 57 °F, low 24 °F 57°24° MarApril: average high 65 °F, low 31 °F 65°31° AprMay: average high 73 °F, low 42 °F 73°42° MayJune: average high 85 °F, low 52 °F 85°52° JunJuly: average high 92 °F, low 58 °F 92°58° JulAugust: average high 90 °F, low 56 °F 90°56° AugSeptember: average high 82 °F, low 47 °F 82°47° SepOctober: average high 68 °F, low 34 °F 68°34° OctNovember: average high 55 °F, low 22 °F 55°22° NovDecember: average high 44 °F, low 14 °F 44°14° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″January: 0.31 in precipitation, 2.9 in snowfall 0.3❄3 JanFebruary: 0.50 in precipitation, 6.5 in snowfall 0.5❄7 FebMarch: 0.89 in precipitation, 3.6 in snowfall 0.9❄4 MarApril: 1.80 in precipitation, 3 in snowfall 1.8❄3 AprMay: 2.75 in precipitation, 0.4 in snowfall 2.8 MayJune: 2.63 in precipitation 2.6 JunJuly: 2.61 in precipitation 2.6 JulAugust: 2.09 in precipitation 2.1 AugSeptember: 1.38 in precipitation, 0.1 in snowfall 1.4 SepOctober: 1.16 in precipitation, 1.6 in snowfall 1.2❄2 OctNovember: 0.45 in precipitation, 2.6 in snowfall 0.5❄3 NovDecember: 0.33 in precipitation, 4.7 in snowfall 0.3❄5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Crook, CO (12 mi away); precipitation: Crook, CO (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

807475b
Peetz, CO · 12 mi
807285b
Fleming, CO · 14 mi
807265b
Crook, CO · 15 mi
807515b
Sterling, CO · 16 mi
807455b
Padroni, CO · 21 mi
691625b
Sidney, NE · 22 mi
691605b
Sidney, NE · 28 mi
807415b
Merino, CO · 29 mi

Colorado planting zones →

Questions about 80736

What planting zone is ZIP code 80736?

ZIP code 80736 (Iliff, 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 Iliff, CO?

The median last spring frost (32 °F) near 80736 is May 11; after May 23 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Crook station.

When is the first frost in Iliff, CO?

The median first fall frost near 80736 is October 4, giving a median frost-free growing season of 145 days.

When should I plant tomatoes in 80736?

Start tomato seeds indoors around Mar 16 – Mar 30 and set transplants outside around May 18 – Jun 1, one to three weeks after the median last frost.

How much rain and snow does 80736 get?

About 16.9 inches of precipitation a year and 25 inches of snowfall (NOAA 1991–2020 normals, Crook station).

How hot do summers get in Iliff, CO?

The average high peaks at 92 °F in July, with about 63 days a year at 90 °F or more.

What kind of soil does 80736 have?

The USDA soil survey maps Wages at the center of ZIP 80736: loam, well drained, pH about 7.2 (neutral).

Did spring come early in Iliff, CO in 2026?

Spring leaf-out near 80736 came on Mar 1 in 2026, 24 days earlier than the 1991–2020 average (Mar 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Iliff, CO?

Long-day onions: the longest day near 80736 is 15 h 06 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 80736 change?

Yes. The 2012 USDA map put 80736 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.