When is the last frost in Olathe, KS?

The average last spring frost (50% probability of 32°F) in Olathe is around April 13, based on NOAA/NCEI 1991–2020 normals at the Olathe Johnson Co Ap, KS station (4.3 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Olathe?

The average first fall frost in Olathe, KS is around October 24, giving roughly a 193-day frost-free growing season.

What planting zone is Olathe, KS?

Olathe is in USDA plant hardiness zone 6b (average annual extreme minimum temperature -5 to 0°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Olathe?

In Olathe, KS the warmest month is July (avg high 88.2°F) and the coldest is January (avg low 20°F). It averages about 40.7″ of precipitation a year and 13.8″ of snow.

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Olathe, KS Planting Calendar & Frost Dates

USDA hardiness zone 6b · ZIP 66061 · elevation 322′ · NOAA & USDA data

Olathe is in USDA hardiness zone 6b (winters can dip to -5 to 0°F), with a growing season of about 193 days between the average last spring frost (April 13) and first fall frost (October 24). The warmest month is July (avg high 88.2°F); the coldest is January (avg low 20°F). It averages 40.7″ of precipitation a year and 13.8″ of snow, mostly mid-winter. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp -5 to 0°F

Last spring frost

April 13

avg (50% prob, 32°F)

First fall frost

October 24

avg (50% prob, 32°F)

Growing season

193 days

frost-free window

Warmest month

July

avg high 88.2°F

Month-by-month typical weather in Olathe

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Olathe 3e, KS (6.5 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	38.7	20	29.3	1.3	3.9
February	44.3	23.9	34.1	1.7	3.3
March	54.9	33.7	44.3	2.5	1.4
April	65.1	43.9	54.5	4.1	0.3
May	74.5	55.5	65	5.3	0
June	83.6	64.9	74.3	5.2	0
July	88.2	69.4	78.8	4.8	0
August	86.8	66.9	76.9	4.5	0
September	79.1	58.4	68.8	4.3	0
October	67.7	46.7	57.2	3.1	0.3
November	54.3	34.6	44.5	2.4	1.2
December	42.5	24.6	33.5	1.8	3.4

What to plant when in Olathe

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: March 2 · Transplant out: April 20
Peppers	warm	Start seeds indoors: February 16 · Transplant out: April 27
Cucumbers	warm	Direct sow: April 20
Zucchini / squash	warm	Direct sow: April 20
Bush beans	warm	Direct sow: April 20
Sweet corn	warm	Direct sow: April 20
Basil	warm	Transplant out: April 20
Peas	cool	Sow (spring): March 9 · Sow (fall): August 29
Spinach	cool	Sow (spring): March 2 · Sow (fall): August 29
Lettuce	cool	Sow (spring): March 16 · Sow (fall): August 29
Kale	cool	Transplant (spring): March 23 · Sow (fall): August 15
Broccoli	cool	Transplant (spring): March 30
Carrots	cool	Sow (spring): March 23 · Sow (fall): August 15
Onions	cool	Transplant (spring): March 16
Potatoes	cool	Plant seed potatoes: March 30
Radishes	cool	Sow (spring): March 16 · Sow (fall): September 12

Dates are computed from Olathe's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in Kansas

Lenexa, KS Overland Park, KS Shawnee, KS Lawrence, KS Kansas City, KS Topeka, KS Manhattan, KS Salina, KS

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Olathe Johnson Co Ap, KS, 4.3 mi (confidence: high). Monthly weather normals: Olathe 3e, KS, 6.5 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.