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

Planting zone for 80528 — Fort Collins, CO

ZIP code 80528 (Fort Collins, Larimer County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 3 and the first fall frost October 6.

Where ZIP 80528 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 3
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 Fort Collins, 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 Fort Collins, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 3median — 50% chance of a later frost
Safe for tender plantsMay 15only 10% chance of frost after
First fall frostOctober 6median — 10% chance by Sep 22
Growing season154 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 23 and returns around October 14.

From the NOAA station Ft Collins 4 E, CO — 6 miles away, elevation 4,922 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 80528

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 22 – Apr 5
SpinachSow outdoors · Mar 22 – Apr 12
Broccoli, cabbageStart indoors · Feb 22 – Mar 8
Broccoli, cabbageTransplant · Apr 12 – Apr 26
Onion setsPlant outdoors · Apr 5 – Apr 19
PotatoesPlant outdoors · Apr 12 – Apr 26
LettuceSow outdoors · Apr 5 – Apr 19
Carrots, beetsSow outdoors · Apr 12 – Apr 26
TomatoesStart indoors · Mar 8 – Mar 22
TomatoesTransplant · May 10 – May 24
Peppers, eggplantStart indoors · Feb 22 – Mar 8
Peppers, eggplantTransplant · May 17 – May 31
BeansSow outdoors · May 10 – May 24
Sweet cornSow outdoors · May 10 – May 24
Cucumbers, squashSow outdoors · May 10 – May 24
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 3) 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 80528 came on Feb 26 — 28 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 Fort Collins, CO.

Soil in Fort Collins, CO

The soil mapped at the center of ZIP 80528 is Wiley — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH7.9alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Wiley silt loam, 1 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 80528; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Fort Collins, CO

Summer high88 °Faverage high, July
Winter low15 °Faverage low, January
Hot days32days a year at 90 °F or more
Freezing nights166nights a year at 32 °F or less
Growing degree days2,614base 50 °F — the season’s usable heat
Longest day15 h 04 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)
Precipitation15.5 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 43 °F, low 15 °F 43°15° JanFebruary: average high 45 °F, low 18 °F 45°18° FebMarch: average high 55 °F, low 26 °F 55°26° MarApril: average high 61 °F, low 34 °F 61°34° AprMay: average high 70 °F, low 43 °F 70°43° MayJune: average high 81 °F, low 52 °F 81°52° JunJuly: average high 88 °F, low 58 °F 88°58° JulAugust: average high 85 °F, low 55 °F 85°55° AugSeptember: average high 77 °F, low 47 °F 77°47° SepOctober: average high 63 °F, low 34 °F 63°34° OctNovember: average high 51 °F, low 24 °F 51°24° NovDecember: average high 42 °F, low 16 °F 42°16° Dec

Precipitation by month inches

0″1″2″3″January: 0.44 in precipitation 0.4 JanFebruary: 0.51 in precipitation 0.5 FebMarch: 1.26 in precipitation 1.3 MarApril: 1.93 in precipitation 1.9 AprMay: 2.70 in precipitation 2.7 MayJune: 1.78 in precipitation 1.8 JunJuly: 1.63 in precipitation 1.6 JulAugust: 1.40 in precipitation 1.4 AugSeptember: 1.40 in precipitation 1.4 SepOctober: 1.18 in precipitation 1.2 OctNovember: 0.75 in precipitation 0.8 NovDecember: 0.55 in precipitation 0.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Ft Collins 4 E, CO (6 mi away); precipitation: Windsor 3.8 Wsw, CO (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

805255b
Fort Collins, CO · 3 mi
805475b
Timnath, CO · 3 mi
805505b
Windsor, CO · 6 mi
805515b
Windsor, CO · 6 mi
805265b
Fort Collins, CO · 7 mi
805275b
Fort Collins, CO · 7 mi
805535b
Fort Collins, CO · 7 mi
805395b
Loveland, CO · 8 mi

All 8 ZIP codes in Fort Collins → · Colorado planting zones →

Questions about 80528

What planting zone is ZIP code 80528?

ZIP code 80528 (Fort Collins, 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 Fort Collins, CO?

The median last spring frost (32 °F) near 80528 is May 3; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Ft Collins 4 E station.

When is the first frost in Fort Collins, CO?

The median first fall frost near 80528 is October 6, giving a median frost-free growing season of 154 days.

When should I plant tomatoes in 80528?

Start tomato seeds indoors around Mar 8 – Mar 22 and set transplants outside around May 10 – May 24, one to three weeks after the median last frost.

How much rain and snow does 80528 get?

About 15.5 inches of precipitation a year (NOAA 1991–2020 normals, Windsor 3.8 Wsw station).

How hot do summers get in Fort Collins, CO?

The average high peaks at 88 °F in July, with about 32 days a year at 90 °F or more.

What kind of soil does 80528 have?

The USDA soil survey maps Wiley at the center of ZIP 80528: silt loam, well drained, pH about 7.9 (alkaline).

Did spring come early in Fort Collins, CO in 2026?

Spring leaf-out near 80528 came on Feb 26 in 2026, 28 days earlier than the 1991–2020 average (Mar 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Fort Collins, CO?

Long-day onions: the longest day near 80528 is 15 h 04 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).