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

Planting zone for 65566 — Viburnum, MO

ZIP code 65566 (Viburnum, Iron County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 26 and the first fall frost October 8.

Where ZIP 65566 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 26

First frostOct 8

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 Viburnum, 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 Viburnum, MO

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 26median — 50% chance of a later frost

Safe for tender plantsMay 12only 10% chance of frost after

First fall frostOctober 8median — 10% chance by Sep 25

Growing season164 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 14 and returns around October 18.

From the NOAA station Steelville 2 N, MO — 18 miles away, elevation 699 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 65566

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 15 – Mar 29

SpinachSow outdoors · Mar 15 – Apr 5

Broccoli, cabbageStart indoors · Feb 15 – Mar 1

Broccoli, cabbageTransplant · Apr 5 – Apr 19

Onion setsPlant outdoors · Mar 29 – Apr 12

PotatoesPlant outdoors · Apr 5 – Apr 19

LettuceSow outdoors · Mar 29 – Apr 12

Carrots, beetsSow outdoors · Apr 5 – Apr 19

TomatoesStart indoors · Mar 1 – Mar 15

TomatoesTransplant · May 3 – May 17

Peppers, eggplantStart indoors · Feb 15 – Mar 1

Peppers, eggplantTransplant · May 10 – May 24

BeansSow outdoors · May 3 – May 17

Sweet cornSow outdoors · May 3 – May 17

Cucumbers, squashSow outdoors · May 3 – May 17

Fall lettuce, spinachSow outdoors · Aug 13 – Aug 27

GarlicPlant cloves · Sep 24 – Oct 29

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 26) and first fall frost (Oct 8) 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 65566 came on Mar 1 — 11 days earlier than the 1991–2020 average (Mar 12).

average
Mar 122026
Mar 1

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 Viburnum, MO.

Soil in Viburnum, MO

The soil mapped at the center of ZIP 65566 is Goss — very cobbly silt loam, well drained.

TextureVery cobbly silt loama good balance for most vegetables

pH5.1strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2.5%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Goss very cobbly silt loam, 15 to 50 percent slopes, extremely stony.

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 65566; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Viburnum, MO

Summer high88 °Faverage high, July

Winter low19 °Faverage low, January

Hot days36days a year at 90 °F or more

Freezing nights141nights a year at 32 °F or less

Growing degree days3,539base 50 °F — the season’s usable heat

Longest day14 h 47 mindaylight on June 21

Shortest day9 h 32 mindaylight on December 21

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

Precipitation45.9 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: Steelville 2 N, MO (18 mi away); precipitation: Steelville 10.2 Sse, MO (6 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.

654566b

Davisville, MO · 2 mi

654466b

Cherryville, MO · 6 mi

655656a

Steelville, MO · 7 mi

Missouri planting zones →

Questions about 65566

What planting zone is ZIP code 65566?

ZIP code 65566 (Viburnum, 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 Viburnum, MO?

The median last spring frost (32 °F) near 65566 is April 26; after May 12 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Steelville 2 N station.

When is the first frost in Viburnum, MO?

The median first fall frost near 65566 is October 8, giving a median frost-free growing season of 164 days.

When should I plant tomatoes in 65566?

Start tomato seeds indoors around Mar 1 – Mar 15 and set transplants outside around May 3 – May 17, one to three weeks after the median last frost.

How much rain and snow does 65566 get?

About 45.9 inches of precipitation a year (NOAA 1991–2020 normals, Steelville 10.2 Sse station).

How hot do summers get in Viburnum, MO?

The average high peaks at 88 °F in July, with about 36 days a year at 90 °F or more.

What kind of soil does 65566 have?

The USDA soil survey maps Goss at the center of ZIP 65566: very cobbly silt loam, well drained, pH about 5.1 (strongly acidic).

Did spring come early in Viburnum, MO in 2026?

Spring leaf-out near 65566 came on Mar 1 in 2026, 11 days earlier than the 1991–2020 average (Mar 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Viburnum, MO?

Intermediate onions: the longest day near 65566 is 14 h 47 min, so day-neutral types bulb best; long-day varieties may not bulb fully.