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

Planting zone for 81525 — Mack, CO

ZIP code 81525 (Mack, Mesa County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 27 and the first fall frost October 11.

Where ZIP 81525 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostApr 27
First frostOct 11
2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mack, 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 Mack, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 27median — 50% chance of a later frost
Safe for tender plantsMay 7only 10% chance of frost after
First fall frostOctober 11median — 10% chance by Sep 28
Growing season164 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 18 and returns around October 22.

From the NOAA station Fruita, CO — 15 miles away, elevation 4,498 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 81525

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 16 – Mar 30
SpinachSow outdoors · Mar 16 – Apr 6
Broccoli, cabbageStart indoors · Feb 16 – Mar 2
Broccoli, cabbageTransplant · Apr 6 – Apr 20
Onion setsPlant outdoors · Mar 30 – Apr 13
PotatoesPlant outdoors · Apr 6 – Apr 20
LettuceSow outdoors · Mar 30 – Apr 13
Carrots, beetsSow outdoors · Apr 6 – Apr 20
TomatoesStart indoors · Mar 2 – Mar 16
TomatoesTransplant · May 4 – May 18
Peppers, eggplantStart indoors · Feb 16 – Mar 2
Peppers, eggplantTransplant · May 11 – May 25
BeansSow outdoors · May 4 – May 18
Sweet cornSow outdoors · May 4 – May 18
Cucumbers, squashSow outdoors · May 4 – May 18
Fall lettuce, spinachSow outdoors · Aug 16 – Aug 30
GarlicPlant cloves · Sep 27 – Nov 1
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 27) and first fall frost (Oct 11) 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 81525 came on Mar 11 — 11 days earlier than the 1991–2020 average (Mar 22).

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 7a in Colorado

573 plants native to the lower 48 states, recorded in Colorado, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Trees 28

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 107

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 254

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 171

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 4

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °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 Mack, CO.

Soil in Mack, CO

The soil mapped at the center of ZIP 81525 is Persayo — silty clay loam, well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH8.4alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.25%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Killpack-Persayo complex, 3 to 25 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 81525; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mack, CO

Summer high95 °Faverage high, July
Winter low15 °Faverage low, January
Hot days70days a year at 90 °F or more
Freezing nights167nights a year at 32 °F or less
Growing degree days3,351base 50 °F — the season’s usable heat
Longest day14 h 56 mindaylight on June 21
Shortest day9 h 24 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation9.7 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 39 °F, low 15 °F 39°15° JanFebruary: average high 47 °F, low 21 °F 47°21° FebMarch: average high 59 °F, low 29 °F 59°29° MarApril: average high 67 °F, low 35 °F 67°35° AprMay: average high 78 °F, low 45 °F 78°45° MayJune: average high 89 °F, low 53 °F 89°53° JunJuly: average high 95 °F, low 60 °F 95°60° JulAugust: average high 92 °F, low 58 °F 92°58° AugSeptember: average high 83 °F, low 48 °F 83°48° SepOctober: average high 69 °F, low 36 °F 69°36° OctNovember: average high 54 °F, low 25 °F 54°25° NovDecember: average high 40 °F, low 16 °F 40°16° Dec

Precipitation by month inches

0″1″2″January: 0.75 in precipitation 0.8 JanFebruary: 0.80 in precipitation 0.8 FebMarch: 0.81 in precipitation 0.8 MarApril: 0.66 in precipitation 0.7 AprMay: 0.94 in precipitation 0.9 MayJune: 0.53 in precipitation 0.5 JunJuly: 0.88 in precipitation 0.9 JulAugust: 0.89 in precipitation 0.9 AugSeptember: 1.16 in precipitation 1.2 SepOctober: 0.99 in precipitation 1.0 OctNovember: 0.57 in precipitation 0.6 NovDecember: 0.68 in precipitation 0.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Fruita, CO (15 mi away); precipitation: Mack 5 Nw, CO (2 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.

815217a
Fruita, CO · 9 mi
815246b
Loma, CO · 13 mi
815056b
Grand Junction, CO · 21 mi
815236b
Glade Park, CO · 24 mi
815067a
Grand Junction, CO · 24 mi
815077a
Grand Junction, CO · 24 mi
816306b
De Beque, CO · 26 mi
815017a
Grand Junction, CO · 26 mi

Colorado planting zones →

Questions about 81525

What planting zone is ZIP code 81525?

ZIP code 81525 (Mack, CO) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Mack, CO?

The median last spring frost (32 °F) near 81525 is April 27; after May 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Fruita station.

When is the first frost in Mack, CO?

The median first fall frost near 81525 is October 11, giving a median frost-free growing season of 164 days.

When should I plant tomatoes in 81525?

Start tomato seeds indoors around Mar 2 – Mar 16 and set transplants outside around May 4 – May 18, one to three weeks after the median last frost.

How much rain and snow does 81525 get?

About 9.7 inches of precipitation a year (NOAA 1991–2020 normals, Mack 5 Nw station).

How hot do summers get in Mack, CO?

The average high peaks at 95 °F in July, with about 70 days a year at 90 °F or more.

What kind of soil does 81525 have?

The USDA soil survey maps Persayo at the center of ZIP 81525: silty clay loam, well drained, pH about 8.4 (alkaline).

Did spring come early in Mack, CO in 2026?

Spring leaf-out near 81525 came on Mar 11 in 2026, 11 days earlier than the 1991–2020 average (Mar 22), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mack, CO?

Intermediate onions: the longest day near 81525 is 14 h 56 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 81525 change?

Yes. The 2012 USDA map put 81525 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.