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

Planting zone for 64089 — Smithville, MO

ZIP code 64089 (Smithville, Clay County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 18 and the first fall frost October 20.

Where ZIP 64089 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.

Zone6a−10 to −5 °F
Coldest night−23.3 to −20.6 °C
Last frostApr 18
First frostOct 20
2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Smithville, MO…

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 Smithville, MO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 18median — 50% chance of a later frost
Safe for tender plantsMay 3only 10% chance of frost after
First fall frostOctober 20median — 10% chance by Oct 5
Growing season183 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 7 and returns around October 29.

From the NOAA station Smithville Lake, MO — within 1 mile, elevation 906 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 64089

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 7 – Mar 21
SpinachSow outdoors · Mar 7 – Mar 28
Broccoli, cabbageStart indoors · Feb 7 – Feb 21
Broccoli, cabbageTransplant · Mar 28 – Apr 11
Onion setsPlant outdoors · Mar 21 – Apr 4
PotatoesPlant outdoors · Mar 28 – Apr 11
LettuceSow outdoors · Mar 21 – Apr 4
Carrots, beetsSow outdoors · Mar 28 – Apr 11
TomatoesStart indoors · Feb 21 – Mar 7
TomatoesTransplant · Apr 25 – May 9
Peppers, eggplantStart indoors · Feb 7 – Feb 21
Peppers, eggplantTransplant · May 2 – May 16
BeansSow outdoors · Apr 25 – May 9
Sweet cornSow outdoors · Apr 25 – May 9
Cucumbers, squashSow outdoors · Apr 25 – May 9
Fall lettuce, spinachSow outdoors · Aug 25 – Sep 8
GarlicPlant cloves · Oct 6 – Nov 10
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 18) and first fall frost (Oct 20) 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 64089 came on Feb 25 — 23 days earlier than the 1991–2020 average (Mar 20).

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 6a in Missouri

516 plants native to the lower 48 states, recorded in Missouri, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. Each links to its USDA PLANTS profile.

Trees 68

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Fbald cypress130 ft · blooms mid spring · medium shade tolerance · to −18 °F

Shrubs 82

alternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °FAmerican hornbeam30 ft · blooms mid spring · low shade tolerance · to −34 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °F

Wildflowers & perennials 190

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °F

Grasses 155

alkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °FAmerican cupscale3 ft · blooms early summer · high shade tolerance · to −18 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBicknell's sedge3 ft · blooms late spring · low shade tolerance · to −38 °Fbig bluestem6 ft · blooms summer · high shade tolerance · to −46 °Fblister sedge3 ft · blooms late spring · medium shade tolerance · to −38 °F

Vines 10

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °Fmuscadine30 ft · blooms late spring · medium shade tolerance · to −18 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °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 Smithville, MO.

Soil in Smithville, MO

The soil mapped at the center of ZIP 64089 is Wiota — 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 matter2.5%moderate
Hydrologic groupCwater soaks in slowly
Farmland classprime farmlandUSDA classification

Map unit: Wiota silt loam, 0 to 2 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 64089; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Smithville, MO

Summer high87 °Faverage high, July
Winter low16 °Faverage low, January
Hot days30days a year at 90 °F or more
Freezing nights119nights a year at 32 °F or less
Growing degree days3,705base 50 °F — the season’s usable heat
Longest day14 h 57 mindaylight on June 21
Shortest day9 h 23 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation40 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 36 °F, low 16 °F 36°16° JanFebruary: average high 42 °F, low 21 °F 42°21° FebMarch: average high 53 °F, low 31 °F 53°31° MarApril: average high 64 °F, low 41 °F 64°41° AprMay: average high 73 °F, low 53 °F 73°53° MayJune: average high 82 °F, low 63 °F 82°63° JunJuly: average high 87 °F, low 68 °F 87°68° JulAugust: average high 85 °F, low 66 °F 85°66° AugSeptember: average high 78 °F, low 56 °F 78°56° SepOctober: average high 66 °F, low 44 °F 66°44° OctNovember: average high 53 °F, low 31 °F 53°31° NovDecember: average high 42 °F, low 22 °F 42°22° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 1.15 in precipitation 1.1 JanFebruary: 1.40 in precipitation 1.4 FebMarch: 2.29 in precipitation 2.3 MarApril: 3.85 in precipitation 3.9 AprMay: 5.38 in precipitation 5.4 MayJune: 5.27 in precipitation 5.3 JunJuly: 4.87 in precipitation 4.9 JulAugust: 4.36 in precipitation 4.4 AugSeptember: 4.30 in precipitation 4.3 SepOctober: 3.47 in precipitation 3.5 OctNovember: 2.10 in precipitation 2.1 NovDecember: 1.59 in precipitation 1.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Smithville Lake, MO (within 1 mile); precipitation: Smithville Lake, MO (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

641656a
Kansas City, MO · 5 mi
641666a
Kansas City, MO · 5 mi
641646b
Kansas City, MO · 5 mi
644926a
Trimble, MO · 6 mi
641676a
Kansas City, MO · 7 mi
641636b
Kansas City, MO · 7 mi
641556b
Kansas City, MO · 8 mi
644446a
Edgerton, MO · 8 mi

Missouri planting zones →

Questions about 64089

What planting zone is ZIP code 64089?

ZIP code 64089 (Smithville, MO) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Smithville, MO?

The median last spring frost (32 °F) near 64089 is April 18; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Smithville Lake station.

When is the first frost in Smithville, MO?

The median first fall frost near 64089 is October 20, giving a median frost-free growing season of 183 days.

When should I plant tomatoes in 64089?

Start tomato seeds indoors around Feb 21 – Mar 7 and set transplants outside around Apr 25 – May 9, one to three weeks after the median last frost.

How much rain and snow does 64089 get?

About 40 inches of precipitation a year (NOAA 1991–2020 normals, Smithville Lake station).

How hot do summers get in Smithville, MO?

The average high peaks at 87 °F in July, with about 30 days a year at 90 °F or more.

What kind of soil does 64089 have?

The USDA soil survey maps Wiota at the center of ZIP 64089: silt loam, well drained, pH about 7.0 (neutral).

Did spring come early in Smithville, MO in 2026?

Spring leaf-out near 64089 came on Feb 25 in 2026, 23 days earlier than the 1991–2020 average (Mar 20), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Smithville, MO?

Intermediate onions: the longest day near 64089 is 14 h 57 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 64089 change?

Yes. The 2012 USDA map put 64089 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.