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

Planting zone for 80737 — Julesburg, CO

ZIP code 80737 (Julesburg, Sedgwick County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 7 and the first fall frost October 6.

Where ZIP 80737 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 7
First frostOct 6
2012 zone5b

Same zone as on the 2012 map. 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 Julesburg, 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 Julesburg, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 7median — 50% chance of a later frost
Safe for tender plantsMay 18only 10% chance of frost after
First fall frostOctober 6median — 10% chance by Sep 23
Growing season152 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 27 and returns around October 15.

From the NOAA station Julesburg, CO — 7 miles away, elevation 3,478 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 80737

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 26 – Apr 9
SpinachSow outdoors · Mar 26 – Apr 16
Broccoli, cabbageStart indoors · Feb 26 – Mar 12
Broccoli, cabbageTransplant · Apr 16 – Apr 30
Onion setsPlant outdoors · Apr 9 – Apr 23
PotatoesPlant outdoors · Apr 16 – Apr 30
LettuceSow outdoors · Apr 9 – Apr 23
Carrots, beetsSow outdoors · Apr 16 – Apr 30
TomatoesStart indoors · Mar 12 – Mar 26
TomatoesTransplant · May 14 – May 28
Peppers, eggplantStart indoors · Feb 26 – Mar 12
Peppers, eggplantTransplant · May 21 – Jun 4
BeansSow outdoors · May 14 – May 28
Sweet cornSow outdoors · May 14 – May 28
Cucumbers, squashSow outdoors · May 14 – May 28
Fall lettuce, spinachSow outdoors · Aug 11 – Aug 25
GarlicPlant cloves · Sep 22 – Oct 27
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 7) and first fall frost (Oct 6) 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 80737 came on Mar 2 — 24 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).

Soil in Julesburg, CO

The soil mapped at the center of ZIP 80737 is Keith — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH7.0neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Keith, goshen, and kuma silt loams, 0 to 3 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 80737; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Julesburg, CO

Summer high88 °Faverage high, July
Winter low16 °Faverage low, January
Hot days48days a year at 90 °F or more
Freezing nights163nights a year at 32 °F or less
Growing degree days2,910base 50 °F — the season’s usable heat
Longest day15 h 07 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)
Precipitation18.6 inper year, rain and melted snow
Snowfall22 inper year; 18 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 41 °F, low 16 °F 41°16° JanFebruary: average high 44 °F, low 18 °F 44°18° FebMarch: average high 55 °F, low 26 °F 55°26° MarApril: average high 62 °F, low 35 °F 62°35° AprMay: average high 71 °F, low 45 °F 71°45° MayJune: average high 82 °F, low 55 °F 82°55° JunJuly: average high 88 °F, low 61 °F 88°61° JulAugust: average high 85 °F, low 59 °F 85°59° AugSeptember: average high 78 °F, low 49 °F 78°49° SepOctober: average high 65 °F, low 35 °F 65°35° OctNovember: average high 51 °F, low 24 °F 51°24° NovDecember: average high 41 °F, low 16 °F 41°16° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.41 in precipitation, 3.7 in snowfall 0.4❄4 JanFebruary: 0.41 in precipitation, 4 in snowfall 0.4❄4 FebMarch: 1.00 in precipitation, 3.3 in snowfall 1.0❄3 MarApril: 1.77 in precipitation, 2.3 in snowfall 1.8❄2 AprMay: 3.00 in precipitation, 0.1 in snowfall 3.0 MayJune: 3.20 in precipitation 3.2 JunJuly: 2.33 in precipitation 2.3 JulAugust: 2.79 in precipitation 2.8 AugSeptember: 1.52 in precipitation 1.5 SepOctober: 1.43 in precipitation, 2 in snowfall 1.4❄2 OctNovember: 0.41 in precipitation, 2.8 in snowfall 0.4❄3 NovDecember: 0.29 in precipitation, 3.5 in snowfall 0.3❄4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Julesburg, CO (7 mi away); precipitation: Julesburg, CO (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

807445b
Ovid, CO · 10 mi
807215b
Amherst, CO · 14 mi
691685b
Venango, NE · 15 mi
691225b
Big Springs, NE · 15 mi
691295b
Chappell, NE · 19 mi
691275b
Brule, NE · 21 mi
691405b
Grant, NE · 23 mi
807465b
Paoli, CO · 24 mi

Colorado planting zones →

Questions about 80737

What planting zone is ZIP code 80737?

ZIP code 80737 (Julesburg, 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 Julesburg, CO?

The median last spring frost (32 °F) near 80737 is May 7; after May 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Julesburg station.

When is the first frost in Julesburg, CO?

The median first fall frost near 80737 is October 6, giving a median frost-free growing season of 152 days.

When should I plant tomatoes in 80737?

Start tomato seeds indoors around Mar 12 – Mar 26 and set transplants outside around May 14 – May 28, one to three weeks after the median last frost.

How much rain and snow does 80737 get?

About 18.6 inches of precipitation a year and 22 inches of snowfall (NOAA 1991–2020 normals, Julesburg station).

How hot do summers get in Julesburg, CO?

The average high peaks at 88 °F in July, with about 48 days a year at 90 °F or more.

What kind of soil does 80737 have?

The USDA soil survey maps Keith at the center of ZIP 80737: silt loam, well drained, pH about 7.0 (neutral).

Did spring come early in Julesburg, CO in 2026?

Spring leaf-out near 80737 came on Mar 2 in 2026, 24 days earlier than the 1991–2020 average (Mar 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Julesburg, CO?

Long-day onions: the longest day near 80737 is 15 h 07 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).