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

Planting zone for 66939 — Courtland, KS

ZIP code 66939 (Courtland, Republic County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 17 and the first fall frost October 21.

Where ZIP 66939 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.

Zone6a−10 to −5 °F

Coldest night−23.3 to −20.6 °C

Last frostApr 17

First frostOct 21

2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Courtland, KS…

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 Courtland, KS

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 17median — 50% chance of a later frost

Safe for tender plantsApril 29only 10% chance of frost after

First fall frostOctober 21median — 10% chance by Oct 5

Growing season187 daysfrost-free, median

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

From the NOAA station Courtland, KS — 5 miles away, elevation 1,499 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 66939

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 6 – Mar 20

SpinachSow outdoors · Mar 6 – Mar 27

Broccoli, cabbageStart indoors · Feb 6 – Feb 20

Broccoli, cabbageTransplant · Mar 27 – Apr 10

Onion setsPlant outdoors · Mar 20 – Apr 3

PotatoesPlant outdoors · Mar 27 – Apr 10

LettuceSow outdoors · Mar 20 – Apr 3

Carrots, beetsSow outdoors · Mar 27 – Apr 10

TomatoesStart indoors · Feb 20 – Mar 6

TomatoesTransplant · Apr 24 – May 8

Peppers, eggplantStart indoors · Feb 6 – Feb 20

Peppers, eggplantTransplant · May 1 – May 15

BeansSow outdoors · Apr 24 – May 8

Sweet cornSow outdoors · Apr 24 – May 8

Cucumbers, squashSow outdoors · Apr 24 – May 8

Fall lettuce, spinachSow outdoors · Aug 26 – Sep 9

GarlicPlant cloves · Oct 7 – Nov 11

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 17) and first fall frost (Oct 21) 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 66939 came on Mar 8 — 15 days earlier than the 1991–2020 average (Mar 23).

average
Mar 232026
Mar 8

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 6a in Kansas

425 plants native to the lower 48 states, recorded in Kansas, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. 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 Courtland, KS.

Soil in Courtland, KS

The soil mapped at the center of ZIP 66939 is Crete — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables

pH5.7moderately acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter3%moderate

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Crete silt loam, 1 to 3 percent slopes, loess plains and breaks.

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 66939; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Courtland, KS

Summer high92 °Faverage high, July

Winter low18 °Faverage low, January

Hot days51days a year at 90 °F or more

Freezing nights137nights a year at 32 °F or less

Growing degree days4,181base 50 °F — the season’s usable heat

Longest day15 h 00 mindaylight on June 21

Shortest day9 h 20 mindaylight on December 21

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

Precipitation29.9 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: Courtland, KS (5 mi away); precipitation: Courtland, KS (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

Belleville, KS · 14 mi

Kansas planting zones →

Questions about 66939

What planting zone is ZIP code 66939?

ZIP code 66939 (Courtland, KS) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Courtland, KS?

The median last spring frost (32 °F) near 66939 is April 17; after April 29 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Courtland station.

When is the first frost in Courtland, KS?

The median first fall frost near 66939 is October 21, giving a median frost-free growing season of 187 days.

When should I plant tomatoes in 66939?

Start tomato seeds indoors around Feb 20 – Mar 6 and set transplants outside around Apr 24 – May 8, one to three weeks after the median last frost.

How much rain and snow does 66939 get?

About 29.9 inches of precipitation a year (NOAA 1991–2020 normals, Courtland station).

How hot do summers get in Courtland, KS?

The average high peaks at 92 °F in July, with about 51 days a year at 90 °F or more.

What kind of soil does 66939 have?

The USDA soil survey maps Crete at the center of ZIP 66939: silt loam, moderately well drained, pH about 5.7 (moderately acidic).

Did spring come early in Courtland, KS in 2026?

Spring leaf-out near 66939 came on Mar 8 in 2026, 15 days earlier than the 1991–2020 average (Mar 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Courtland, KS?

Intermediate onions: the longest day near 66939 is 15 h 00 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 66939 change?

Yes. The 2012 USDA map put 66939 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.