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

Planting zone for 73947 — Keyes, OK

ZIP code 73947 (Keyes, Cimarron County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 19 and the first fall frost October 23.

Where ZIP 73947 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.

Zone6b−5 to 0 °F

Coldest night−20.6 to −17.8 °C

Last frostApr 19

First frostOct 23

2012 zone6b

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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Keyes, 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 Keyes, OK

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 19median — 50% chance of a later frost

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

First fall frostOctober 23median — 10% chance by Oct 9

Growing season186 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 8 and returns around November 1.

From the NOAA station Elkhart, KS — 19 miles away, elevation 3,599 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 73947

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 8 – Mar 22

SpinachSow outdoors · Mar 8 – Mar 29

Broccoli, cabbageStart indoors · Feb 8 – Feb 22

Broccoli, cabbageTransplant · Mar 29 – Apr 12

Onion setsPlant outdoors · Mar 22 – Apr 5

PotatoesPlant outdoors · Mar 29 – Apr 12

LettuceSow outdoors · Mar 22 – Apr 5

Carrots, beetsSow outdoors · Mar 29 – Apr 12

TomatoesStart indoors · Feb 22 – Mar 8

TomatoesTransplant · Apr 26 – May 10

Peppers, eggplantStart indoors · Feb 8 – Feb 22

Peppers, eggplantTransplant · May 3 – May 17

BeansSow outdoors · Apr 26 – May 10

Sweet cornSow outdoors · Apr 26 – May 10

Cucumbers, squashSow outdoors · Apr 26 – May 10

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 19) 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 73947 came on Feb 17 — 19 days earlier than the 1991–2020 average (Mar 8).

average
Mar 82026
Feb 17

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 6b in Oklahoma

489 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 6b. 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 Keyes, OK.

Soil in Keyes, OK

The soil mapped at the center of ZIP 73947 is Sherm — clay loam, well drained.

TextureClay loamholds water and nutrients; slow to drain and warm up

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: Sherm clay loam, 0 to 1 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 73947; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Keyes, OK

Summer high93 °Faverage high, July

Winter low21 °Faverage low, January

Hot days75days a year at 90 °F or more

Freezing nights121nights a year at 32 °F or less

Growing degree days4,107base 50 °F — the season’s usable heat

Longest day14 h 41 mindaylight on June 21

Shortest day9 h 38 mindaylight on December 21

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

Precipitation18.4 inper year, rain and melted snow

Snowfall18 inper year; 14 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: Elkhart, KS (19 mi away); precipitation: Elkhart, KS (19 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

Boise City, OK · 24 mi

Richfield, KS · 31 mi

739607a

Texhoma, TX · 32 mi

Oklahoma planting zones →

Questions about 73947

What planting zone is ZIP code 73947?

ZIP code 73947 (Keyes, OK) 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 Keyes, OK?

The median last spring frost (32 °F) near 73947 is April 19; after May 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Elkhart station.

When is the first frost in Keyes, OK?

The median first fall frost near 73947 is October 23, giving a median frost-free growing season of 186 days.

When should I plant tomatoes in 73947?

Start tomato seeds indoors around Feb 22 – Mar 8 and set transplants outside around Apr 26 – May 10, one to three weeks after the median last frost.

How much rain and snow does 73947 get?

About 18.4 inches of precipitation a year and 18 inches of snowfall (NOAA 1991–2020 normals, Elkhart station).

How hot do summers get in Keyes, OK?

The average high peaks at 93 °F in July, with about 75 days a year at 90 °F or more.

What kind of soil does 73947 have?

The USDA soil survey maps Sherm at the center of ZIP 73947: clay loam, well drained, pH about 7.2 (neutral).

Did spring come early in Keyes, OK in 2026?

Spring leaf-out near 73947 came on Feb 17 in 2026, 19 days earlier than the 1991–2020 average (Mar 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Keyes, OK?

Intermediate onions: the longest day near 73947 is 14 h 41 min, so day-neutral types bulb best; long-day varieties may not bulb fully.