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

Planting zone for 67356 — Oswego, KS

ZIP code 67356 (Oswego, Labette County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 11 and the first fall frost October 26.

Where ZIP 67356 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 11

First frostOct 26

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 Oswego, 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 Oswego, KS

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 11median — 50% chance of a later frost

Safe for tender plantsApril 26only 10% chance of frost after

First fall frostOctober 26median — 10% chance by Oct 13

Growing season196 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 1 and returns around November 2.

From the NOAA station Parsons 2 Nw, KS — 16 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 67356

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 28 – Mar 14

SpinachSow outdoors · Feb 28 – Mar 21

Broccoli, cabbageStart indoors · Jan 31 – Feb 14

Broccoli, cabbageTransplant · Mar 21 – Apr 4

Onion setsPlant outdoors · Mar 14 – Mar 28

PotatoesPlant outdoors · Mar 21 – Apr 4

LettuceSow outdoors · Mar 14 – Mar 28

Carrots, beetsSow outdoors · Mar 21 – Apr 4

TomatoesStart indoors · Feb 14 – Feb 28

TomatoesTransplant · Apr 18 – May 2

Peppers, eggplantStart indoors · Jan 31 – Feb 14

Peppers, eggplantTransplant · Apr 25 – May 9

BeansSow outdoors · Apr 18 – May 2

Sweet cornSow outdoors · Apr 18 – May 2

Cucumbers, squashSow outdoors · Apr 18 – May 2

Fall lettuce, spinachSow outdoors · Aug 31 – Sep 14

GarlicPlant cloves · Oct 12 – Nov 16

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 11) and first fall frost (Oct 26) 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 67356 came on Feb 19 — 16 days earlier than the 1991–2020 average (Mar 7).

average
Mar 72026
Feb 19

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).

Soil in Oswego, KS

The soil mapped at the center of ZIP 67356 is Olpe — gravelly silt loam, well drained.

TextureGravelly silt loama good balance for most vegetables

pH5.8moderately acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Olpe-Dennis complex, 3 to 7 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 67356; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Oswego, KS

Summer high90 °Faverage high, July

Winter low22 °Faverage low, January

Hot days47days a year at 90 °F or more

Freezing nights104nights a year at 32 °F or less

Growing degree days4,288base 50 °F — the season’s usable heat

Longest day14 h 43 mindaylight on June 21

Shortest day9 h 36 mindaylight on December 21

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

Precipitation46.1 inper year, rain and melted snow

Snowfall4 inper year; 7 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: Parsons 2 Nw, KS (16 mi away); precipitation: Oswego 1 N, KS (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

West Mineral, KS · 14 mi

673547a

Mound Valley, KS · 15 mi

Kansas planting zones →

Questions about 67356

What planting zone is ZIP code 67356?

ZIP code 67356 (Oswego, 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 Oswego, KS?

The median last spring frost (32 °F) near 67356 is April 11; after April 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Parsons 2 Nw station.

When is the first frost in Oswego, KS?

The median first fall frost near 67356 is October 26, giving a median frost-free growing season of 196 days.

When should I plant tomatoes in 67356?

Start tomato seeds indoors around Feb 14 – Feb 28 and set transplants outside around Apr 18 – May 2, one to three weeks after the median last frost.

How much rain and snow does 67356 get?

About 46.1 inches of precipitation a year and 4 inches of snowfall (NOAA 1991–2020 normals, Oswego 1 N station).

How hot do summers get in Oswego, KS?

The average high peaks at 90 °F in July, with about 47 days a year at 90 °F or more.

What kind of soil does 67356 have?

The USDA soil survey maps Olpe at the center of ZIP 67356: gravelly silt loam, well drained, pH about 5.8 (moderately acidic).

Did spring come early in Oswego, KS in 2026?

Spring leaf-out near 67356 came on Feb 19 in 2026, 16 days earlier than the 1991–2020 average (Mar 7), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Oswego, KS?

Intermediate onions: the longest day near 67356 is 14 h 43 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 67356 change?

Yes. The 2012 USDA map put 67356 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.