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

Planting zone for 73557 — Medicine Park, OK

ZIP code 73557 (Medicine Park, Comanche County) is in USDA zone 8a: the coldest winter night averages 10 to 15 °F. The median last spring frost is March 21 and the first fall frost November 12.

Where ZIP 73557 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.

Zone8a10 to 15 °F

Coldest night−12.2 to −9.4 °C

Last frostMar 21

First frostNov 12

2012 zone7a

Was 7a on the 2012 map — a full zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 8a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Medicine Park, 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 Medicine Park, OK

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 21median — 50% chance of a later frost

Safe for tender plantsApril 8only 10% chance of frost after

First fall frostNovember 12median — 10% chance by Oct 27

Growing season234 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 6 and returns around November 22.

From the NOAA station Medicine Pk 3w Mesonet, OK — 4 miles away, elevation 1,598 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 73557

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 7 – Feb 21

SpinachSow outdoors · Feb 7 – Feb 28

Broccoli, cabbageStart indoors · Jan 10 – Jan 24

Broccoli, cabbageTransplant · Feb 28 – Mar 14

Onion setsPlant outdoors · Feb 21 – Mar 7

PotatoesPlant outdoors · Feb 28 – Mar 14

LettuceSow outdoors · Feb 21 – Mar 7

Carrots, beetsSow outdoors · Feb 28 – Mar 14

TomatoesStart indoors · Jan 24 – Feb 7

TomatoesTransplant · Mar 28 – Apr 11

Peppers, eggplantStart indoors · Jan 10 – Jan 24

Peppers, eggplantTransplant · Apr 4 – Apr 18

BeansSow outdoors · Mar 28 – Apr 11

Sweet cornSow outdoors · Mar 28 – Apr 11

Cucumbers, squashSow outdoors · Mar 28 – Apr 11

Fall lettuce, spinachSow outdoors · Sep 17 – Oct 1

GarlicPlant cloves · Oct 29 – Dec 3

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 21) and first fall frost (Nov 12) 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 73557 came on Feb 9 — 10 days earlier than the 1991–2020 average (Feb 19).

average
Feb 192026
Feb 9

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 8a in Oklahoma

525 plants native to the lower 48 states, recorded in Oklahoma, and rated by the USDA to survive 10 °F or colder — the bottom of zone 8a. 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 Medicine Park, OK.

Soil in Medicine Park, OK

The soil mapped at the center of ZIP 73557 is Brico — cobbly loam, well drained.

TextureCobbly loama good balance for most vegetables

pH6.3slightly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Brico soils and Rock outcrop, 5 to 50 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 73557; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Medicine Park, OK

Summer high94 °Faverage high, July

Winter low31 °Faverage low, January

Hot days84days a year at 90 °F or more

Freezing nights55nights a year at 32 °F or less

Growing degree days5,463base 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

Precipitation32.3 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: Medicine Pk 3w Mesonet, OK (4 mi away); precipitation: Medicine Pk 3w Mesonet, OK (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

5 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 73557

What planting zone is ZIP code 73557?

ZIP code 73557 (Medicine Park, OK) is in USDA hardiness zone 8a on the 2023 map: the coldest night of an average winter reaches 10 to 15 °F (−12.2 to −9.4 °C).

When is the last frost in Medicine Park, OK?

The median last spring frost (32 °F) near 73557 is March 21; after April 8 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Medicine Pk 3w Mesonet station.

When is the first frost in Medicine Park, OK?

The median first fall frost near 73557 is November 12, giving a median frost-free growing season of 234 days.

When should I plant tomatoes in 73557?

Start tomato seeds indoors around Jan 24 – Feb 7 and set transplants outside around Mar 28 – Apr 11, one to three weeks after the median last frost.

How much rain and snow does 73557 get?

About 32.3 inches of precipitation a year (NOAA 1991–2020 normals, Medicine Pk 3w Mesonet station).

How hot do summers get in Medicine Park, OK?

The average high peaks at 94 °F in July, with about 84 days a year at 90 °F or more.

What kind of soil does 73557 have?

The USDA soil survey maps Brico at the center of ZIP 73557: cobbly loam, well drained, pH about 6.3 (slightly acidic).

Did spring come early in Medicine Park, OK in 2026?

Spring leaf-out near 73557 came on Feb 9 in 2026, 10 days earlier than the 1991–2020 average (Feb 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Medicine Park, OK?

Intermediate onions: the longest day near 73557 is 14 h 29 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 73557 change?

Yes. The 2012 USDA map put 73557 in zone 7a; the 2023 map puts it in zone 8a. The newer map uses 1991–2020 data and more weather stations.