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

Planting zone for 66086 — Tonganoxie, KS

ZIP code 66086 (Tonganoxie, Leavenworth County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 21 and the first fall frost October 17.

Where ZIP 66086 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 21

First frostOct 17

2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Tonganoxie, 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 Tonganoxie, KS

JanFebMarAprMayJunJulAugSepOctNovDec

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

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

Safe for tender plantsMay 6only 10% chance of frost after

First fall frostOctober 17median — 10% chance by Sep 29

Growing season177 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 10 and returns around October 27.

From the NOAA station Lawrence Municipal Airport, KS — 10 miles away, elevation 833 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 66086

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 10 – Mar 24

SpinachSow outdoors · Mar 10 – Mar 31

Broccoli, cabbageStart indoors · Feb 10 – Feb 24

Broccoli, cabbageTransplant · Mar 31 – Apr 14

Onion setsPlant outdoors · Mar 24 – Apr 7

PotatoesPlant outdoors · Mar 31 – Apr 14

LettuceSow outdoors · Mar 24 – Apr 7

Carrots, beetsSow outdoors · Mar 31 – Apr 14

TomatoesStart indoors · Feb 24 – Mar 10

TomatoesTransplant · Apr 28 – May 12

Peppers, eggplantStart indoors · Feb 10 – Feb 24

Peppers, eggplantTransplant · May 5 – May 19

BeansSow outdoors · Apr 28 – May 12

Sweet cornSow outdoors · Apr 28 – May 12

Cucumbers, squashSow outdoors · Apr 28 – May 12

Fall lettuce, spinachSow outdoors · Aug 22 – Sep 5

GarlicPlant cloves · Oct 3 – Nov 7

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 21) and first fall frost (Oct 17) 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 66086 came on Feb 25 — 21 days earlier than the 1991–2020 average (Mar 18).

average
Mar 182026
Feb 25

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 Kansas

431 plants native to the lower 48 states, recorded in Kansas, 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 Tonganoxie, KS.

Soil in Tonganoxie, KS

The soil mapped at the center of ZIP 66086 is Elmont — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH6.2slightly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Elmont silt loam, 3 to 7 percent slopes, eroded.

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 66086; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Tonganoxie, KS

Summer high91 °Faverage high, July

Winter low18 °Faverage low, January

Hot days52days a year at 90 °F or more

Freezing nights123nights a year at 32 °F or less

Growing degree days4,125base 50 °F — the season’s usable heat

Longest day14 h 55 mindaylight on June 21

Shortest day9 h 25 mindaylight on December 21

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

Precipitation38.8 inper year, rain and melted snow

Snowfall12 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Lawrence Municipal Airport, KS (10 mi away); precipitation: Tonganoxie 5se, KS (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

Bonner Springs, KS · 9 mi

660186b

De Soto, KS · 12 mi

660486b

Leavenworth, KS · 12 mi

662266b

Shawnee, KS · 13 mi

Kansas planting zones →

Questions about 66086

What planting zone is ZIP code 66086?

ZIP code 66086 (Tonganoxie, KS) 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 Tonganoxie, KS?

The median last spring frost (32 °F) near 66086 is April 21; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lawrence Municipal Airport station.

When is the first frost in Tonganoxie, KS?

The median first fall frost near 66086 is October 17, giving a median frost-free growing season of 177 days.

When should I plant tomatoes in 66086?

Start tomato seeds indoors around Feb 24 – Mar 10 and set transplants outside around Apr 28 – May 12, one to three weeks after the median last frost.

How much rain and snow does 66086 get?

About 38.8 inches of precipitation a year and 12 inches of snowfall (NOAA 1991–2020 normals, Tonganoxie 5se station).

How hot do summers get in Tonganoxie, KS?

The average high peaks at 91 °F in July, with about 52 days a year at 90 °F or more.

What kind of soil does 66086 have?

The USDA soil survey maps Elmont at the center of ZIP 66086: silt loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Tonganoxie, KS in 2026?

Spring leaf-out near 66086 came on Feb 25 in 2026, 21 days earlier than the 1991–2020 average (Mar 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Tonganoxie, KS?

Intermediate onions: the longest day near 66086 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 66086 change?

Yes. The 2012 USDA map put 66086 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.