Olathe, KS Frost Dates
Published: February 1, 2026 · Updated: April 23, 2026
USDA Zone 6b
Last Spring Frost
March 22
Safe to transplant after this date
First Fall Frost
November 10
Protect tender plants before this date
Frost-Free Season
233 days
Late March to Late November
295 days until last frost in Olathe — March 22
Olathe’s zone 6b climate provides a generous 233-day frost-free window — long enough for a wide variety of vegetables and excellent conditions for both cool-season and warm-season lawn grasses.
Complete Planting Calendar for Olathe
Lawn Care Timing for Olathe
Based on Olathe's USDA zone 6b frost dates: The last frost of March 22 marks when warm-season grasses begin recovering. Apply spring fertilizer in Late March when soil reaches 55°F. The first fall frost of November 10 sets your deadlines — complete overseeding by September 1–October 15 and apply winterizer by Late November.
USDA Zone 6b Summary
About 7.5 months frost-free. Classic transition zone. Tall Fescue performs best here.
Frequently Asked Questions
What is the last frost date in Olathe, KS?
The average last spring frost in Olathe is March 22. This is based on USDA zone 6b historical averages. Plan transplanting and spring lawn care around this date — wait 2 weeks after for frost-sensitive plantings.
When is the first fall frost in Olathe?
Olathe’s average first fall frost is November 10. This sets deadlines for fall overseeding (must be done 6 weeks before) and winterizer application (by Late November).
When should I plant tomatoes in Olathe?
Transplant tomato seedlings outdoors after March 22. Start seeds indoors Early January. Direct sow warm-season crops after april 1.
When should I overseed my lawn in Olathe?
The prime overseeding window in Olathe is September 1–October 15. This ensures warm soil for germination before the first fall frost on November 10.
When should I apply winterizer in Olathe?
Apply winterizer fertilizer in Olathe by Late November. This high-potassium application hardens grass cell walls before freeze damage. Your first fall frost of November 10 is the hard deadline.