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

Planting zone for 81643 — Mesa, CO

ZIP code 81643 (Mesa, Mesa County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 17 and the first fall frost October 26.

Where ZIP 81643 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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostApr 17
First frostOct 26
2012 zone6b

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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mesa, 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 Mesa, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 17median — 50% chance of a later frost
Safe for tender plantsMay 3only 10% chance of frost after
First fall frostOctober 26median — 10% chance by Oct 12
Growing season190 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 1 and returns around November 5.

From the NOAA station Palisade, CO — 11 miles away, elevation 4,751 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 81643

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 6 – Mar 20
SpinachSow outdoors · Mar 6 – Mar 27
Broccoli, cabbageStart indoors · Feb 6 – Feb 20
Broccoli, cabbageTransplant · Mar 27 – Apr 10
Onion setsPlant outdoors · Mar 20 – Apr 3
PotatoesPlant outdoors · Mar 27 – Apr 10
LettuceSow outdoors · Mar 20 – Apr 3
Carrots, beetsSow outdoors · Mar 27 – Apr 10
TomatoesStart indoors · Feb 20 – Mar 6
TomatoesTransplant · Apr 24 – May 8
Peppers, eggplantStart indoors · Feb 6 – Feb 20
Peppers, eggplantTransplant · May 1 – May 15
BeansSow outdoors · Apr 24 – May 8
Sweet cornSow outdoors · Apr 24 – May 8
Cucumbers, squashSow outdoors · Apr 24 – May 8
Fall lettuce, spinachSow outdoors · Aug 31 – Sep 14
GarlicPlant cloves · Oct 12 – Nov 16
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 17) and first fall frost (Oct 26) 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 81643 came on Mar 19 — 17 days earlier than the 1991–2020 average (Apr 5).

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 6b in Colorado

565 plants native to the lower 48 states, recorded in Colorado, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. 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 104

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 252

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 168

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 Mesa, CO.

Soil in Mesa, CO

The soil mapped at the center of ZIP 81643 is Golime — cobbly loam, well drained.

TextureCobbly loama good balance for most vegetables
pH7.0neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Golime cobbly loam, 5 to 15 percent slopes, very bouldery.

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 81643; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mesa, CO

Summer high93 °Faverage high, July
Winter low21 °Faverage low, January
Hot days60days a year at 90 °F or more
Freezing nights119nights a year at 32 °F or less
Growing degree days3,732base 50 °F — the season’s usable heat
Longest day14 h 55 mindaylight on June 21
Shortest day9 h 25 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation33.6 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 40 °F, low 21 °F 40°21° JanFebruary: average high 47 °F, low 26 °F 47°26° FebMarch: average high 58 °F, low 35 °F 58°35° MarApril: average high 66 °F, low 40 °F 66°40° AprMay: average high 76 °F, low 50 °F 76°50° MayJune: average high 87 °F, low 59 °F 87°59° JunJuly: average high 93 °F, low 65 °F 93°65° JulAugust: average high 90 °F, low 63 °F 90°63° AugSeptember: average high 81 °F, low 55 °F 81°55° SepOctober: average high 67 °F, low 42 °F 67°42° OctNovember: average high 53 °F, low 31 °F 53°31° NovDecember: average high 41 °F, low 22 °F 41°22° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.40 in precipitation 3.4 JanFebruary: 3.51 in precipitation 3.5 FebMarch: 3.91 in precipitation 3.9 MarApril: 4.01 in precipitation 4.0 AprMay: 3.11 in precipitation 3.1 MayJune: 1.13 in precipitation 1.1 JunJuly: 1.46 in precipitation 1.5 JulAugust: 1.81 in precipitation 1.8 AugSeptember: 2.23 in precipitation 2.2 SepOctober: 3.07 in precipitation 3.1 OctNovember: 2.77 in precipitation 2.8 NovDecember: 3.18 in precipitation 3.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Palisade, CO (11 mi away); precipitation: Mesa Lakes, CO (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

816465b
Molina, CO · 8 mi
815267a
Palisade, CO · 11 mi
815207a
Clifton, CO · 15 mi
814186b
Eckert, CO · 16 mi
814135b
Cedaredge, CO · 17 mi
815047a
Grand Junction, CO · 18 mi
815037a
Grand Junction, CO · 19 mi
815027a
Grand Junction, CO · 19 mi

Colorado planting zones →

Questions about 81643

What planting zone is ZIP code 81643?

ZIP code 81643 (Mesa, CO) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Mesa, CO?

The median last spring frost (32 °F) near 81643 is April 17; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Palisade station.

When is the first frost in Mesa, CO?

The median first fall frost near 81643 is October 26, giving a median frost-free growing season of 190 days.

When should I plant tomatoes in 81643?

Start tomato seeds indoors around Feb 20 – Mar 6 and set transplants outside around Apr 24 – May 8, one to three weeks after the median last frost.

How much rain and snow does 81643 get?

About 33.6 inches of precipitation a year (NOAA 1991–2020 normals, Mesa Lakes station).

How hot do summers get in Mesa, CO?

The average high peaks at 93 °F in July, with about 60 days a year at 90 °F or more.

What kind of soil does 81643 have?

The USDA soil survey maps Golime at the center of ZIP 81643: cobbly loam, well drained, pH about 7.0 (neutral).

Did spring come early in Mesa, CO in 2026?

Spring leaf-out near 81643 came on Mar 19 in 2026, 17 days earlier than the 1991–2020 average (Apr 5), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mesa, CO?

Intermediate onions: the longest day near 81643 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.