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

Planting zone for 73093 — Washington, OK

ZIP code 73093 (Washington, McClain County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 3 and the first fall frost November 3.

Where ZIP 73093 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 3

First frostNov 3

2012 zone7a

Was 7a 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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Washington, 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 Washington, OK

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 3median — 50% chance of a later frost

Safe for tender plantsApril 18only 10% chance of frost after

First fall frostNovember 3median — 10% chance by Oct 21

Growing season212 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 23 and returns around November 12.

From the NOAA station Norman 3sse, OK — 6 miles away, elevation 1,129 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 73093

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 20 – Mar 6

SpinachSow outdoors · Feb 20 – Mar 13

Broccoli, cabbageStart indoors · Jan 23 – Feb 6

Broccoli, cabbageTransplant · Mar 13 – Mar 27

Onion setsPlant outdoors · Mar 6 – Mar 20

PotatoesPlant outdoors · Mar 13 – Mar 27

LettuceSow outdoors · Mar 6 – Mar 20

Carrots, beetsSow outdoors · Mar 13 – Mar 27

TomatoesStart indoors · Feb 6 – Feb 20

TomatoesTransplant · Apr 10 – Apr 24

Peppers, eggplantStart indoors · Jan 23 – Feb 6

Peppers, eggplantTransplant · Apr 17 – May 1

BeansSow outdoors · Apr 10 – Apr 24

Sweet cornSow outdoors · Apr 10 – Apr 24

Cucumbers, squashSow outdoors · Apr 10 – Apr 24

Fall lettuce, spinachSow outdoors · Sep 8 – Sep 22

GarlicPlant cloves · Oct 20 – Nov 24

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 3) and first fall frost (Nov 3) 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 73093 came on Feb 12 — 9 days earlier than the 1991–2020 average (Feb 21).

average
Feb 212026
Feb 12

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 Washington, OK

The soil mapped at the center of ZIP 73093 is Nash — loam, well drained.

TextureLoama good balance for most vegetables

pH7.3neutral; 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: Nash-Lucien complex, 3 to 5 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 73093; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Washington, OK

Summer high93 °Faverage high, July

Winter low28 °Faverage low, January

Hot days69days a year at 90 °F or more

Freezing nights77nights a year at 32 °F or less

Growing degree days5,109base 50 °F — the season’s usable heat

Longest day14 h 31 mindaylight on June 21

Shortest day9 h 47 mindaylight on December 21

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

Precipitation36.7 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: Norman 3sse, OK (6 mi away); precipitation: Norman 5.9 Sw, OK (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7b.

Oklahoma planting zones →

Questions about 73093

What planting zone is ZIP code 73093?

ZIP code 73093 (Washington, 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 Washington, OK?

The median last spring frost (32 °F) near 73093 is April 3; after April 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Norman 3sse station.

When is the first frost in Washington, OK?

The median first fall frost near 73093 is November 3, giving a median frost-free growing season of 212 days.

When should I plant tomatoes in 73093?

Start tomato seeds indoors around Feb 6 – Feb 20 and set transplants outside around Apr 10 – Apr 24, one to three weeks after the median last frost.

How much rain and snow does 73093 get?

About 36.7 inches of precipitation a year (NOAA 1991–2020 normals, Norman 5.9 Sw station).

How hot do summers get in Washington, OK?

The average high peaks at 93 °F in July, with about 69 days a year at 90 °F or more.

What kind of soil does 73093 have?

The USDA soil survey maps Nash at the center of ZIP 73093: loam, well drained, pH about 7.3 (neutral).

Did spring come early in Washington, OK in 2026?

Spring leaf-out near 73093 came on Feb 12 in 2026, 9 days earlier than the 1991–2020 average (Feb 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Washington, OK?

Intermediate onions: the longest day near 73093 is 14 h 31 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 73093 change?

Yes. The 2012 USDA map put 73093 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.