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

Planting zone for 73440 — Lebanon, OK

ZIP code 73440 (Lebanon, Marshall County) is in USDA zone 8a: the coldest winter night averages 10 to 15 °F. The median last spring frost is March 24 and the first fall frost November 6.

Where ZIP 73440 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.

Zone8a10 to 15 °F
Coldest night−12.2 to −9.4 °C
Last frostMar 24
First frostNov 6
2012 zone7b

Was 7b 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 8a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Lebanon, OK…

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 Lebanon, OK

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 24median — 50% chance of a later frost
Safe for tender plantsApril 17only 10% chance of frost after
First fall frostNovember 6median — 10% chance by Oct 21
Growing season226 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 10 and returns around November 15.

From the NOAA station Madill 11wsw Mesonet, OK — 6 miles away, elevation 761 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 73440

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 10 – Feb 24
SpinachSow outdoors · Feb 10 – Mar 3
Broccoli, cabbageStart indoors · Jan 13 – Jan 27
Broccoli, cabbageTransplant · Mar 3 – Mar 17
Onion setsPlant outdoors · Feb 24 – Mar 10
PotatoesPlant outdoors · Mar 3 – Mar 17
LettuceSow outdoors · Feb 24 – Mar 10
Carrots, beetsSow outdoors · Mar 3 – Mar 17
TomatoesStart indoors · Jan 27 – Feb 10
TomatoesTransplant · Mar 31 – Apr 14
Peppers, eggplantStart indoors · Jan 13 – Jan 27
Peppers, eggplantTransplant · Apr 7 – Apr 21
BeansSow outdoors · Mar 31 – Apr 14
Sweet cornSow outdoors · Mar 31 – Apr 14
Cucumbers, squashSow outdoors · Mar 31 – Apr 14
Fall lettuce, spinachSow outdoors · Sep 11 – Sep 25
GarlicPlant cloves · Oct 23 – Nov 27
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 24) and first fall frost (Nov 6) 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 73440 came on Feb 10 — 3 days earlier than the 1991–2020 average (Feb 13).

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 Lebanon, OK

The soil mapped at the center of ZIP 73440 is Konawa — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH5.8moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classprime farmlandUSDA classification

Map unit: Konawa fine sandy loam, 1 to 3 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 73440; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Lebanon, OK

Summer high95 °Faverage high, August
Winter low31 °Faverage low, January
Hot days86days a year at 90 °F or more
Freezing nights59nights a year at 32 °F or less
Growing degree days5,638base 50 °F — the season’s usable heat
Longest day14 h 25 mindaylight on June 21
Shortest day9 h 53 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation42.7 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 54 °F, low 31 °F 54°31° JanFebruary: average high 58 °F, low 36 °F 58°36° FebMarch: average high 66 °F, low 43 °F 66°43° MarApril: average high 74 °F, low 51 °F 74°51° AprMay: average high 81 °F, low 60 °F 81°60° MayJune: average high 89 °F, low 69 °F 89°69° JunJuly: average high 93 °F, low 72 °F 93°72° JulAugust: average high 95 °F, low 71 °F 95°71° AugSeptember: average high 87 °F, low 63 °F 87°63° SepOctober: average high 76 °F, low 52 °F 76°52° OctNovember: average high 65 °F, low 42 °F 65°42° NovDecember: average high 55 °F, low 34 °F 55°34° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 2.13 in precipitation 2.1 JanFebruary: 2.53 in precipitation 2.5 FebMarch: 3.96 in precipitation 4.0 MarApril: 3.42 in precipitation 3.4 AprMay: 5.72 in precipitation 5.7 MayJune: 4.56 in precipitation 4.6 JunJuly: 2.88 in precipitation 2.9 JulAugust: 2.46 in precipitation 2.5 AugSeptember: 3.44 in precipitation 3.4 SepOctober: 4.79 in precipitation 4.8 OctNovember: 3.65 in precipitation 3.6 NovDecember: 3.16 in precipitation 3.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Madill 11wsw Mesonet, OK (6 mi away); precipitation: Gordonville 3.6 Nne, TX (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 8a.

734398a
Kingston, OK · 8 mi
762458a
Gordonville, TX · 10 mi
734468a
Madill, OK · 11 mi
734488a
Marietta, OK · 12 mi
750768a
Pottsboro, TX · 15 mi
762648a
Sadler, TX · 15 mi
762738a
Whitesboro, TX · 15 mi
747318a
Cartwright, OK · 19 mi

Oklahoma planting zones →

Questions about 73440

What planting zone is ZIP code 73440?

ZIP code 73440 (Lebanon, OK) is in USDA hardiness zone 8a on the 2023 map: the coldest night of an average winter reaches 10 to 15 °F (−12.2 to −9.4 °C).

When is the last frost in Lebanon, OK?

The median last spring frost (32 °F) near 73440 is March 24; after April 17 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Madill 11wsw Mesonet station.

When is the first frost in Lebanon, OK?

The median first fall frost near 73440 is November 6, giving a median frost-free growing season of 226 days.

When should I plant tomatoes in 73440?

Start tomato seeds indoors around Jan 27 – Feb 10 and set transplants outside around Mar 31 – Apr 14, one to three weeks after the median last frost.

How much rain and snow does 73440 get?

About 42.7 inches of precipitation a year (NOAA 1991–2020 normals, Gordonville 3.6 Nne station).

How hot do summers get in Lebanon, OK?

The average high peaks at 95 °F in August, with about 86 days a year at 90 °F or more.

What kind of soil does 73440 have?

The USDA soil survey maps Konawa at the center of ZIP 73440: fine sandy loam, well drained, pH about 5.8 (moderately acidic).

Did spring come early in Lebanon, OK in 2026?

Spring leaf-out near 73440 came on Feb 10 in 2026, 3 days earlier than the 1991–2020 average (Feb 13), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Lebanon, OK?

Intermediate onions: the longest day near 73440 is 14 h 25 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 73440 change?

Yes. The 2012 USDA map put 73440 in zone 7b; the 2023 map puts it in zone 8a. The newer map uses 1991–2020 data and more weather stations.