Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 73550 — Hollis, OK

ZIP code 73550 (Hollis, Harmon County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 5 and the first fall frost October 31.

Where ZIP 73550 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 5

First frostOct 31

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 Hollis, 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 Hollis, OK

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 5median — 50% chance of a later frost

Safe for tender plantsApril 21only 10% chance of frost after

First fall frostOctober 31median — 10% chance by Oct 16

Growing season208 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 25 and returns around November 7.

From the NOAA station Hollis 5e Mesonet, OK — 4 miles away, elevation 1,631 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 73550

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 22 – Mar 8

SpinachSow outdoors · Feb 22 – Mar 15

Broccoli, cabbageStart indoors · Jan 25 – Feb 8

Broccoli, cabbageTransplant · Mar 15 – Mar 29

Onion setsPlant outdoors · Mar 8 – Mar 22

PotatoesPlant outdoors · Mar 15 – Mar 29

LettuceSow outdoors · Mar 8 – Mar 22

Carrots, beetsSow outdoors · Mar 15 – Mar 29

TomatoesStart indoors · Feb 8 – Feb 22

TomatoesTransplant · Apr 12 – Apr 26

Peppers, eggplantStart indoors · Jan 25 – Feb 8

Peppers, eggplantTransplant · Apr 19 – May 3

BeansSow outdoors · Apr 12 – Apr 26

Sweet cornSow outdoors · Apr 12 – Apr 26

Cucumbers, squashSow outdoors · Apr 12 – Apr 26

Fall lettuce, spinachSow outdoors · Sep 5 – Sep 19

GarlicPlant cloves · Oct 17 – Nov 21

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 5) and first fall frost (Oct 31) 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 73550 came on Feb 12 — 7 days earlier than the 1991–2020 average (Feb 19).

average
Feb 192026
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).

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 Hollis, OK.

Soil in Hollis, OK

The soil mapped at the center of ZIP 73550 is Devol — loamy sand, well drained.

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

pH6.0slightly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.5%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Devol and Springer loamy sands, 3 to 8 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 73550; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hollis, OK

Summer high96 °Faverage high, July

Winter low26 °Faverage low, January

Hot days111days a year at 90 °F or more

Freezing nights89nights a year at 32 °F or less

Growing degree days5,340base 50 °F — the season’s usable heat

Longest day14 h 29 mindaylight on June 21

Shortest day9 h 49 mindaylight on December 21

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

Precipitation25.8 inper year, rain and melted snow

Snowfall3 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Hollis 5e Mesonet, OK (4 mi away); precipitation: Hollis 5e, OK (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7b.

Wellington, TX · 21 mi

735607b

Olustee, OK · 28 mi

Oklahoma planting zones →

Questions about 73550

What planting zone is ZIP code 73550?

ZIP code 73550 (Hollis, 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 Hollis, OK?

The median last spring frost (32 °F) near 73550 is April 5; after April 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hollis 5e Mesonet station.

When is the first frost in Hollis, OK?

The median first fall frost near 73550 is October 31, giving a median frost-free growing season of 208 days.

When should I plant tomatoes in 73550?

Start tomato seeds indoors around Feb 8 – Feb 22 and set transplants outside around Apr 12 – Apr 26, one to three weeks after the median last frost.

How much rain and snow does 73550 get?

About 25.8 inches of precipitation a year and 3 inches of snowfall (NOAA 1991–2020 normals, Hollis 5e station).

How hot do summers get in Hollis, OK?

The average high peaks at 96 °F in July, with about 111 days a year at 90 °F or more.

What kind of soil does 73550 have?

The USDA soil survey maps Devol at the center of ZIP 73550: loamy sand, well drained, pH about 6.0 (slightly acidic).

Did spring come early in Hollis, OK in 2026?

Spring leaf-out near 73550 came on Feb 12 in 2026, 7 days earlier than the 1991–2020 average (Feb 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hollis, OK?

Intermediate onions: the longest day near 73550 is 14 h 29 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 73550 change?

Yes. The 2012 USDA map put 73550 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.