Chart of First and Last Frost Dates by Zone

First and Last Frost Dates: A Comprehensive Guide by USDA Hardiness Zones

As the seasons transition and temperatures fluctuate, gardeners across the United States eagerly await the arrival of spring and dread the chill of autumn. One crucial factor in successful gardening is understanding the first and last frost dates specific to your USDA Hardiness Zone. You can find your Zone by entering your zip code: on desktop at the link above in the black bar "My Growing Zone"; on mobile by linking to any project page and selecting "Find My Planting Zone" link at the top of the page.

Understanding Frost Dates

Frost dates mark the beginning and end of the frost-free growing season, serving as a valuable reference point for garden planning. The last frost date in spring is the date after which the risk of frost is significantly reduced, making it safer to transplant tender plants outdoors. The first frost date in fall, on the other hand, signifies the return of colder temperatures and the potential for frost damage to sensitive vegetation.


USDA Hardiness Zones

The USDA Hardiness Zone Map divides the United States into 13 zones based on average minimum winter temperatures. Each zone is further divided into subsets "a" and "b," indicating slight temperature variations. Knowing your specific zone helps you determine the best plants to grow in your region and when to start planting. Park Seed's app, From Seed to Spoon, will calculate these dates for you and provide you with the ideal timing for garden tasks conveniently on your phone. And that's just one of the tools the app provides. It will also help you identify pests and beneficials, learn about the nutrients your garden provides and how they help your overall wellness or support specific health issues. Check it out!

First and Last Frost Dates by USDA Hardiness Zones

Zone First Frost Date Last Frost Date
1a July 15 - July 31 June 1 - June 15
1b July 15 - July 31 June 1 - June 15
2a September 1 - September 15 May 1 - May 15
2b September 1 - September 15 May 1 - May 15
3a, 3b September 15 - September 30 April 15 - April 30
4a, 4b October 1 - October 15 April 15 - April 30
5a – 7a October 15 - October 31 April 1 - April 15
7b November 1 - November 15 March 15 - March 31
8a November 15 - November 30 March 1 - March 15
8b November 15 - November 30 February 15 - February 28
9a December 1 - December 15 February 1 - February 15
9b December 1 - December 15 January 15 - January 31
10a, 10b December 15 - December 31 January 1 - January 15
11a – 13 Frost-free year-round Frost-free year-round

Understanding your USDA Hardiness Zone's first and last frost dates empowers you to make informed decisions about when to start planting, transplant, and prepare for the colder months. If you prefer to have those dates calculated for you (yes, please!), get our app From Seed to Spoon.