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

Planting zone for 73403 — Ardmore, OK

ZIP code 73403 (Ardmore, Carter County) is in USDA zone 8a: the coldest winter night averages 10 to 15 °F. The median last spring frost is March 15 and the first fall frost November 14.

Where ZIP 73403 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.

Zone8a10 to 15 °F

Coldest night−12.2 to −9.4 °C

Last frostMar 15

First frostNov 14

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 Ardmore, 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 Ardmore, OK

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 15median — 50% chance of a later frost

Safe for tender plantsApril 2only 10% chance of frost after

First fall frostNovember 14median — 10% chance by Oct 29

Growing season244 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 3 and returns around November 26.

From the NOAA station Ardmore, OK — within 1 mile, elevation 840 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 73403

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 1 – Feb 15

SpinachSow outdoors · Feb 1 – Feb 22

Broccoli, cabbageStart indoors · Jan 4 – Jan 18

Broccoli, cabbageTransplant · Feb 22 – Mar 8

Onion setsPlant outdoors · Feb 15 – Mar 1

PotatoesPlant outdoors · Feb 22 – Mar 8

LettuceSow outdoors · Feb 15 – Mar 1

Carrots, beetsSow outdoors · Feb 22 – Mar 8

TomatoesStart indoors · Jan 18 – Feb 1

TomatoesTransplant · Mar 22 – Apr 5

Peppers, eggplantStart indoors · Jan 4 – Jan 18

Peppers, eggplantTransplant · Mar 29 – Apr 12

BeansSow outdoors · Mar 22 – Apr 5

Sweet cornSow outdoors · Mar 22 – Apr 5

Cucumbers, squashSow outdoors · Mar 22 – Apr 5

Fall lettuce, spinachSow outdoors · Sep 19 – Oct 3

GarlicPlant cloves · Oct 31 – Dec 5

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 15) and first fall frost (Nov 14) 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 73403 came on Feb 10 — about the same time as the 1991–2020 average (Feb 12).

average
Feb 122026
Feb 10

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 8a in Oklahoma

525 plants native to the lower 48 states, recorded in Oklahoma, and rated by the USDA to survive 10 °F or colder — the bottom of zone 8a. 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 Ardmore, OK.

Soil in Ardmore, OK

The soil mapped at the center of ZIP 73403 is Durant — loam, moderately well drained.

TextureLoama good balance for most vegetables

pH5.8moderately acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter2%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classprime farmlandUSDA classification

Map unit: Durant 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 73403; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Ardmore, OK

Summer high95 °Faverage high, July

Winter low32 °Faverage low, January

Hot days81days a year at 90 °F or more

Freezing nights46nights a year at 32 °F or less

Growing degree days6,080base 50 °F — the season’s usable heat

Longest day14 h 26 mindaylight on June 21

Shortest day9 h 52 mindaylight on December 21

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

Precipitation38 inper year, rain and melted snow

Snowfall3 inper year; 1 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: Ardmore, OK (within 1 mile); precipitation: Ardmore, OK (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 8a.

734018a

Ardmore, OK · 3 mi

734438a

Lone Grove, OK · 9 mi

734368a

Gene Autry, OK · 10 mi

734028a

Ardmore, OK · 10 mi

734538a

Overbrook, OK · 12 mi

Dougherty, OK · 17 mi

All 3 ZIP codes in Ardmore → · Oklahoma planting zones →

Questions about 73403

What planting zone is ZIP code 73403?

ZIP code 73403 (Ardmore, 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 Ardmore, OK?

The median last spring frost (32 °F) near 73403 is March 15; after April 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Ardmore station.

When is the first frost in Ardmore, OK?

The median first fall frost near 73403 is November 14, giving a median frost-free growing season of 244 days.

When should I plant tomatoes in 73403?

Start tomato seeds indoors around Jan 18 – Feb 1 and set transplants outside around Mar 22 – Apr 5, one to three weeks after the median last frost.

How much rain and snow does 73403 get?

About 38 inches of precipitation a year and 3 inches of snowfall (NOAA 1991–2020 normals, Ardmore station).

How hot do summers get in Ardmore, OK?

The average high peaks at 95 °F in July, with about 81 days a year at 90 °F or more.

What kind of soil does 73403 have?

The USDA soil survey maps Durant at the center of ZIP 73403: loam, moderately well drained, pH about 5.8 (moderately acidic).

Did spring come early in Ardmore, OK in 2026?

Spring leaf-out near 73403 came on Feb 10 in 2026, about the same as the 1991–2020 average (Feb 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Ardmore, OK?

Intermediate onions: the longest day near 73403 is 14 h 26 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 73403 change?

Yes. The 2012 USDA map put 73403 in zone 7b; the 2023 map puts it in zone 8a. The newer map uses 1991–2020 data and more weather stations.