Arizona Frost Dates
Published: February 1, 2026 · Updated: April 23, 2026
Last Spring Frost
January 30
Zone 9a
First Fall Frost
December 15
Zone 9a
Frost-Free Season
319 days
Year-round to Year-round
Lawn Care Timing for Arizona
Vegetable Garden Timing for Arizona
Frost Dates by City in Arizona
Frequently Asked Questions
What is the last frost date in Arizona?
The average last spring frost in Arizona (zone 9a) is January 30. Dates vary by city and elevation. Find your specific city below for exact dates.
When is it safe to plant tomatoes in Arizona?
Transplant tomato seedlings outdoors after January 30 — the average last frost date for zone 9a. Start seeds indoors September (for fall garden). Wait 2 weeks after last frost for extra safety.
When should I overseed my lawn in Arizona?
The prime overseeding window in Arizona is October–November. This ensures 6 weeks of warm soil for germination before the first fall frost on December 15.
When should I apply winteriser in Arizona?
Apply winteriser fertiliser by Not typically needed. Your first fall frost of December 15 is the hard deadline — apply at least 2–3 weeks before.
What USDA zone is Arizona?
Arizona contains USDA zones 7b, 9a, 9b. Each zone has different frost dates and growing seasons. Find your city below for your specific zone.