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

Planting zone for 63433 — Ashburn, MO

ZIP code 63433 (Ashburn, Pike County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 4 and the first fall frost November 4.

Where ZIP 63433 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 4

First frostNov 4

2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Ashburn, 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 Ashburn, MO

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 4median — 50% chance of a later frost

Safe for tender plantsApril 19only 10% chance of frost after

First fall frostNovember 4median — 10% chance by Oct 23

Growing season212 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 26 and returns around November 14.

From the NOAA station Saverton L&D 22, MO — 11 miles away, elevation 472 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 63433

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 21 – Mar 7

SpinachSow outdoors · Feb 21 – Mar 14

Broccoli, cabbageStart indoors · Jan 24 – Feb 7

Broccoli, cabbageTransplant · Mar 14 – Mar 28

Onion setsPlant outdoors · Mar 7 – Mar 21

PotatoesPlant outdoors · Mar 14 – Mar 28

LettuceSow outdoors · Mar 7 – Mar 21

Carrots, beetsSow outdoors · Mar 14 – Mar 28

TomatoesStart indoors · Feb 7 – Feb 21

TomatoesTransplant · Apr 11 – Apr 25

Peppers, eggplantStart indoors · Jan 24 – Feb 7

Peppers, eggplantTransplant · Apr 18 – May 2

BeansSow outdoors · Apr 11 – Apr 25

Sweet cornSow outdoors · Apr 11 – Apr 25

Cucumbers, squashSow outdoors · Apr 11 – Apr 25

Fall lettuce, spinachSow outdoors · Sep 9 – Sep 23

GarlicPlant cloves · Oct 21 – Nov 25

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 4) and first fall frost (Nov 4) 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 63433 came on Mar 9 — 12 days earlier than the 1991–2020 average (Mar 21).

average
Mar 212026
Mar 9

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 Missouri

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

Soil in Ashburn, MO

The soil mapped at the center of ZIP 63433 is Moniteau — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables

pH5.7moderately acidic; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter1.7%low — add compost

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Moniteau silt loam, 0 to 2 percent slopes, occasionally flooded.

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 63433; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Ashburn, MO

Summer high89 °Faverage high, July

Winter low21 °Faverage low, January

Hot days37days a year at 90 °F or more

Freezing nights105nights a year at 32 °F or less

Growing degree days4,121base 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

Precipitation37.3 inper year, rain and melted snow

Snowfall10 inper year; 14 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Saverton L&D 22, MO (11 mi away); precipitation: Louisiana, MO (6 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.

633536a

Louisiana, MO · 4 mi

623566b

New Canton, IL · 6 mi

623706b

Rockport, IL · 6 mi

634416a

Frankford, MO · 11 mi

623666b

Pleasant Hill, IL · 12 mi

634676b

Saverton, MO · 12 mi

623456a

Kinderhook, IL · 13 mi

623126a

Barry, IL · 14 mi

Missouri planting zones →

Questions about 63433

What planting zone is ZIP code 63433?

ZIP code 63433 (Ashburn, MO) 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 Ashburn, MO?

The median last spring frost (32 °F) near 63433 is April 4; after April 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Saverton L&D 22 station.

When is the first frost in Ashburn, MO?

The median first fall frost near 63433 is November 4, giving a median frost-free growing season of 212 days.

When should I plant tomatoes in 63433?

Start tomato seeds indoors around Feb 7 – Feb 21 and set transplants outside around Apr 11 – Apr 25, one to three weeks after the median last frost.

How much rain and snow does 63433 get?

About 37.3 inches of precipitation a year and 10 inches of snowfall (NOAA 1991–2020 normals, Louisiana station).

How hot do summers get in Ashburn, MO?

The average high peaks at 89 °F in July, with about 37 days a year at 90 °F or more.

What kind of soil does 63433 have?

The USDA soil survey maps Moniteau at the center of ZIP 63433: silt loam, poorly drained, pH about 5.7 (moderately acidic).

Did spring come early in Ashburn, MO in 2026?

Spring leaf-out near 63433 came on Mar 9 in 2026, 12 days earlier than the 1991–2020 average (Mar 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Ashburn, MO?

Intermediate onions: the longest day near 63433 is 14 h 58 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 63433 change?

Yes. The 2012 USDA map put 63433 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.