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

Planting zone for 73942 — Guymon, OK

ZIP code 73942 (Guymon, Texas County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 18 and the first fall frost October 23.

Where ZIP 73942 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 18

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 Guymon, 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 Guymon, OK

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 18median — 50% chance of a later frost

Safe for tender plantsMay 1only 10% chance of frost after

First fall frostOctober 23median — 10% chance by Oct 11

Growing season188 daysfrost-free, median

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

From the NOAA station Guymon Municipal Airport, OK — 4 miles away, elevation 3,124 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 73942

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 7 – Mar 21

SpinachSow outdoors · Mar 7 – Mar 28

Broccoli, cabbageStart indoors · Feb 7 – Feb 21

Broccoli, cabbageTransplant · Mar 28 – Apr 11

Onion setsPlant outdoors · Mar 21 – Apr 4

PotatoesPlant outdoors · Mar 28 – Apr 11

LettuceSow outdoors · Mar 21 – Apr 4

Carrots, beetsSow outdoors · Mar 28 – Apr 11

TomatoesStart indoors · Feb 21 – Mar 7

TomatoesTransplant · Apr 25 – May 9

Peppers, eggplantStart indoors · Feb 7 – Feb 21

Peppers, eggplantTransplant · May 2 – May 16

BeansSow outdoors · Apr 25 – May 9

Sweet cornSow outdoors · Apr 25 – May 9

Cucumbers, squashSow outdoors · Apr 25 – May 9

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 18) 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 73942 came on Feb 16 — 18 days earlier than the 1991–2020 average (Mar 6).

average
Mar 62026
Feb 16

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 Guymon, OK.

Soil in Guymon, OK

The soil mapped at the center of ZIP 73942 is Vona — loamy fine sand, well drained.

TextureLoamy fine sanddrains and warms fast; dries out and needs more feeding

pH7.2neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Vona loamy fine sand, 0 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 73942; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Guymon, OK

Summer high95 °Faverage high, July

Winter low22 °Faverage low, January

Hot days89days a year at 90 °F or more

Freezing nights122nights a year at 32 °F or less

Growing degree days4,437base 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

Precipitation17.8 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: Guymon Municipal Airport, OK (4 mi away); precipitation: Guymon Municipal Airport, OK (4 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.

Oklahoma planting zones →

Questions about 73942

What planting zone is ZIP code 73942?

ZIP code 73942 (Guymon, 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 Guymon, OK?

The median last spring frost (32 °F) near 73942 is April 18; after May 1 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Guymon Municipal Airport station.

When is the first frost in Guymon, OK?

The median first fall frost near 73942 is October 23, giving a median frost-free growing season of 188 days.

When should I plant tomatoes in 73942?

Start tomato seeds indoors around Feb 21 – Mar 7 and set transplants outside around Apr 25 – May 9, one to three weeks after the median last frost.

How much rain and snow does 73942 get?

About 17.8 inches of precipitation a year (NOAA 1991–2020 normals, Guymon Municipal Airport station).

How hot do summers get in Guymon, OK?

The average high peaks at 95 °F in July, with about 89 days a year at 90 °F or more.

What kind of soil does 73942 have?

The USDA soil survey maps Vona at the center of ZIP 73942: loamy fine sand, well drained, pH about 7.2 (neutral).

Did spring come early in Guymon, OK in 2026?

Spring leaf-out near 73942 came on Feb 16 in 2026, 18 days earlier than the 1991–2020 average (Mar 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Guymon, OK?

Intermediate onions: the longest day near 73942 is 14 h 41 min, so day-neutral types bulb best; long-day varieties may not bulb fully.