Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 64439 — Dearborn, MO

ZIP code 64439 (Dearborn, Platte 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 64439 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 zone6a

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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Dearborn, 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 Dearborn, 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 — 14 miles away, 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 64439

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 64439 came on Feb 28 — 21 days earlier than the 1991–2020 average (Mar 21).

average
Mar 212026
Feb 28

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.

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 Dearborn, MO.

Soil in Dearborn, MO

The soil mapped at the center of ZIP 64439 is Higginsville — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH6.5neutral; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.6%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Higginsville silt loam, 5 to 9 percent slopes, eroded.

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 64439; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dearborn, 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 58 mindaylight on June 21

Shortest day9 h 22 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation38.9 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Smithville Lake, MO (14 mi away); precipitation: Platte City 2.9 Nne, MO (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

640186a

Camden Point, MO · 5 mi

Platte City, MO · 11 mi

Missouri planting zones →

Questions about 64439

What planting zone is ZIP code 64439?

ZIP code 64439 (Dearborn, 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 Dearborn, MO?

The median last spring frost (32 °F) near 64439 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 Dearborn, MO?

The median first fall frost near 64439 is October 20, giving a median frost-free growing season of 183 days.

When should I plant tomatoes in 64439?

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 64439 get?

About 38.9 inches of precipitation a year (NOAA 1991–2020 normals, Platte City 2.9 Nne station).

How hot do summers get in Dearborn, 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 64439 have?

The USDA soil survey maps Higginsville at the center of ZIP 64439: silt loam, somewhat poorly drained, pH about 6.5 (neutral).

Did spring come early in Dearborn, MO in 2026?

Spring leaf-out near 64439 came on Feb 28 in 2026, 21 days earlier than the 1991–2020 average (Mar 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Dearborn, MO?

Intermediate onions: the longest day near 64439 is 14 h 58 min, so day-neutral types bulb best; long-day varieties may not bulb fully.