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

Planting zone for 66760 — Opolis, KS

ZIP code 66760 (Opolis, Crawford County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 7 and the first fall frost October 30.

Where ZIP 66760 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.

Zone7a0 to 5 °F

Coldest night−17.8 to −15 °C

Last frostApr 7

First frostOct 30

2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Opolis, 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 Opolis, KS

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 7median — 50% chance of a later frost

Safe for tender plantsApril 24only 10% chance of frost after

First fall frostOctober 30median — 10% chance by Oct 17

Growing season203 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 29 and returns around November 6.

From the NOAA station Pittsburg, KS — 5 miles away, elevation 909 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 66760

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 24 – Mar 10

SpinachSow outdoors · Feb 24 – Mar 17

Broccoli, cabbageStart indoors · Jan 27 – Feb 10

Broccoli, cabbageTransplant · Mar 17 – Mar 31

Onion setsPlant outdoors · Mar 10 – Mar 24

PotatoesPlant outdoors · Mar 17 – Mar 31

LettuceSow outdoors · Mar 10 – Mar 24

Carrots, beetsSow outdoors · Mar 17 – Mar 31

TomatoesStart indoors · Feb 10 – Feb 24

TomatoesTransplant · Apr 14 – Apr 28

Peppers, eggplantStart indoors · Jan 27 – Feb 10

Peppers, eggplantTransplant · Apr 21 – May 5

BeansSow outdoors · Apr 14 – Apr 28

Sweet cornSow outdoors · Apr 14 – Apr 28

Cucumbers, squashSow outdoors · Apr 14 – Apr 28

Fall lettuce, spinachSow outdoors · Sep 4 – Sep 18

GarlicPlant cloves · Oct 16 – Nov 20

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 7) and first fall frost (Oct 30) 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 66760 came on Feb 17 — 17 days earlier than the 1991–2020 average (Mar 6).

average
Mar 62026
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 7a in Kansas

439 plants native to the lower 48 states, recorded in Kansas, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 Opolis, KS.

Soil in Opolis, KS

The soil mapped at the center of ZIP 66760 is Parsons — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH6.1slightly acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.25%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classprime farmlandUSDA classification

Map unit: Parsons silt loam, 1 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 66760; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Opolis, KS

Summer high90 °Faverage high, July

Winter low24 °Faverage low, January

Hot days58days a year at 90 °F or more

Freezing nights91nights a year at 32 °F or less

Growing degree days4,480base 50 °F — the season’s usable heat

Longest day14 h 44 mindaylight on June 21

Shortest day9 h 35 mindaylight on December 21

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

Precipitation45.3 inper year, rain and melted snow

Snowfall8 inper year; 8 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: Pittsburg, KS (5 mi away); precipitation: Waco 4n, MO (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

Mindenmines, MO · 11 mi

648347a

Carl Junction, MO · 12 mi

667737a

Scammon, KS · 12 mi

Kansas planting zones →

Questions about 66760

What planting zone is ZIP code 66760?

ZIP code 66760 (Opolis, KS) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Opolis, KS?

The median last spring frost (32 °F) near 66760 is April 7; after April 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Pittsburg station.

When is the first frost in Opolis, KS?

The median first fall frost near 66760 is October 30, giving a median frost-free growing season of 203 days.

When should I plant tomatoes in 66760?

Start tomato seeds indoors around Feb 10 – Feb 24 and set transplants outside around Apr 14 – Apr 28, one to three weeks after the median last frost.

How much rain and snow does 66760 get?

About 45.3 inches of precipitation a year and 8 inches of snowfall (NOAA 1991–2020 normals, Waco 4n station).

How hot do summers get in Opolis, KS?

The average high peaks at 90 °F in July, with about 58 days a year at 90 °F or more.

What kind of soil does 66760 have?

The USDA soil survey maps Parsons at the center of ZIP 66760: silt loam, somewhat poorly drained, pH about 6.1 (slightly acidic).

Did spring come early in Opolis, KS in 2026?

Spring leaf-out near 66760 came on Feb 17 in 2026, 17 days earlier than the 1991–2020 average (Mar 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Opolis, KS?

Intermediate onions: the longest day near 66760 is 14 h 44 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 66760 change?

Yes. The 2012 USDA map put 66760 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.