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

Planting zone for 73537 — Eldorado, OK

ZIP code 73537 (Eldorado, Jackson County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 4 and the first fall frost November 1.

Where ZIP 73537 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.

Zone7b5 to 10 °F

Coldest night−15 to −12.2 °C

Last frostApr 4

First frostNov 1

2012 zone7b

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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Eldorado, 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 Eldorado, OK

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 22only 10% chance of frost after

First fall frostNovember 1median — 10% chance by Oct 17

Growing season210 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 22 and returns around November 10.

From the NOAA station Quanah 2 Sw, TX — 14 miles away, elevation 1,601 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 73537

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 6 – Sep 20

GarlicPlant cloves · Oct 18 – Nov 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 4) and first fall frost (Nov 1) 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 73537 came on Feb 10 — 8 days earlier than the 1991–2020 average (Feb 18).

average
Feb 182026
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 7b in Oklahoma

518 plants native to the lower 48 states, recorded in Oklahoma, and rated by the USDA to survive 5 °F or colder — the bottom of zone 7b. 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 Eldorado, OK.

Soil in Eldorado, OK

The soil mapped at the center of ZIP 73537 is Frankirk — loam, well drained.

TextureLoama good balance for most vegetables

pH7.2neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Frankirk 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 73537; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Eldorado, OK

Summer high97 °Faverage high, July

Winter low27 °Faverage low, January

Hot days97days a year at 90 °F or more

Freezing nights78nights a year at 32 °F or less

Growing degree days5,483base 50 °F — the season’s usable heat

Longest day14 h 28 mindaylight on June 21

Shortest day9 h 51 mindaylight on December 21

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

Precipitation26.5 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: Quanah 2 Sw, TX (14 mi away); precipitation: Quanah 0.1 Nw, TX (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7b.

Chillicothe, TX · 18 mi

Oklahoma planting zones →

Questions about 73537

What planting zone is ZIP code 73537?

ZIP code 73537 (Eldorado, OK) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Eldorado, OK?

The median last spring frost (32 °F) near 73537 is April 4; after April 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Quanah 2 Sw station.

When is the first frost in Eldorado, OK?

The median first fall frost near 73537 is November 1, giving a median frost-free growing season of 210 days.

When should I plant tomatoes in 73537?

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 73537 get?

About 26.5 inches of precipitation a year (NOAA 1991–2020 normals, Quanah 0.1 Nw station).

How hot do summers get in Eldorado, OK?

The average high peaks at 97 °F in July, with about 97 days a year at 90 °F or more.

What kind of soil does 73537 have?

The USDA soil survey maps Frankirk at the center of ZIP 73537: loam, well drained, pH about 7.2 (neutral).

Did spring come early in Eldorado, OK in 2026?

Spring leaf-out near 73537 came on Feb 10 in 2026, 8 days earlier than the 1991–2020 average (Feb 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Eldorado, OK?

Intermediate onions: the longest day near 73537 is 14 h 28 min, so day-neutral types bulb best; long-day varieties may not bulb fully.