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

Planting zone for 63370 — Olney, MO

ZIP code 63370 (Olney, Lincoln County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 14 and the first fall frost October 23.

Where ZIP 63370 is

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 14
First frostOct 23
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 Olney, 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 Olney, MO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 14median — 50% chance of a later frost
Safe for tender plantsMay 3only 10% chance of frost after
First fall frostOctober 23median — 10% chance by Oct 9
Growing season191 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 3 and returns around November 2.

From the NOAA station Warrenton 1 N, MO — 18 miles away, elevation 827 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 63370

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 3 – Mar 17
SpinachSow outdoors · Mar 3 – Mar 24
Broccoli, cabbageStart indoors · Feb 3 – Feb 17
Broccoli, cabbageTransplant · Mar 24 – Apr 7
Onion setsPlant outdoors · Mar 17 – Mar 31
PotatoesPlant outdoors · Mar 24 – Apr 7
LettuceSow outdoors · Mar 17 – Mar 31
Carrots, beetsSow outdoors · Mar 24 – Apr 7
TomatoesStart indoors · Feb 17 – Mar 3
TomatoesTransplant · Apr 21 – May 5
Peppers, eggplantStart indoors · Feb 3 – Feb 17
Peppers, eggplantTransplant · Apr 28 – May 12
BeansSow outdoors · Apr 21 – May 5
Sweet cornSow outdoors · Apr 21 – May 5
Cucumbers, squashSow outdoors · Apr 21 – May 5
Fall lettuce, spinachSow outdoors · Aug 28 – Sep 11
GarlicPlant cloves · Oct 9 – Nov 13
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 14) and first fall frost (Oct 23) 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 63370 came on Mar 8 — 11 days earlier than the 1991–2020 average (Mar 19).

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).

Soil in Olney, MO

The soil mapped at the center of ZIP 63370 is Mexico — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables
pH6.5neutral; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter1.87%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Mexico 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 63370; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Olney, MO

Summer high88 °Faverage high, July
Winter low20 °Faverage low, January
Hot days31days a year at 90 °F or more
Freezing nights111nights a year at 32 °F or less
Growing degree days3,915base 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
Precipitation41.8 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 39 °F, low 20 °F 39°20° JanFebruary: average high 44 °F, low 23 °F 44°23° FebMarch: average high 55 °F, low 33 °F 55°33° MarApril: average high 66 °F, low 43 °F 66°43° AprMay: average high 75 °F, low 53 °F 75°53° MayJune: average high 84 °F, low 63 °F 84°63° JunJuly: average high 88 °F, low 66 °F 88°66° JulAugust: average high 87 °F, low 65 °F 87°65° AugSeptember: average high 80 °F, low 56 °F 80°56° SepOctober: average high 68 °F, low 45 °F 68°45° OctNovember: average high 55 °F, low 34 °F 55°34° NovDecember: average high 43 °F, low 25 °F 43°25° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 2.00 in precipitation 2.0 JanFebruary: 2.03 in precipitation 2.0 FebMarch: 3.58 in precipitation 3.6 MarApril: 5.06 in precipitation 5.1 AprMay: 5.51 in precipitation 5.5 MayJune: 4.77 in precipitation 4.8 JunJuly: 3.82 in precipitation 3.8 JulAugust: 3.74 in precipitation 3.7 AugSeptember: 3.67 in precipitation 3.7 SepOctober: 2.86 in precipitation 2.9 OctNovember: 2.57 in precipitation 2.6 NovDecember: 2.19 in precipitation 2.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Warrenton 1 N, MO (18 mi away); precipitation: Middletown 3.5 Sw, MO (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

633336b
Bellflower, MO · 5 mi
633816b
Truxton, MO · 7 mi
633596b
Middletown, MO · 8 mi
633776b
Silex, MO · 8 mi
633496b
Hawk Point, MO · 9 mi
633506b
High Hill, MO · 14 mi
633876b
Whiteside, MO · 14 mi
633796b
Troy, MO · 14 mi

Missouri planting zones →

Questions about 63370

What planting zone is ZIP code 63370?

ZIP code 63370 (Olney, 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 Olney, MO?

The median last spring frost (32 °F) near 63370 is April 14; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Warrenton 1 N station.

When is the first frost in Olney, MO?

The median first fall frost near 63370 is October 23, giving a median frost-free growing season of 191 days.

When should I plant tomatoes in 63370?

Start tomato seeds indoors around Feb 17 – Mar 3 and set transplants outside around Apr 21 – May 5, one to three weeks after the median last frost.

How much rain and snow does 63370 get?

About 41.8 inches of precipitation a year (NOAA 1991–2020 normals, Middletown 3.5 Sw station).

How hot do summers get in Olney, MO?

The average high peaks at 88 °F in July, with about 31 days a year at 90 °F or more.

What kind of soil does 63370 have?

The USDA soil survey maps Mexico at the center of ZIP 63370: silt loam, poorly drained, pH about 6.5 (neutral).

Did spring come early in Olney, MO in 2026?

Spring leaf-out near 63370 came on Mar 8 in 2026, 11 days earlier than the 1991–2020 average (Mar 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Olney, MO?

Intermediate onions: the longest day near 63370 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 63370 change?

Yes. The 2012 USDA map put 63370 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.