Frost Dates by Hardiness Zone

• Zone 3b (30 stations)
• Zone 4a (106 stations)
• Zone 4b (172 stations)
• Zone 5a (244 stations)
• Zone 5b (230 stations)
• Zone 6a (272 stations)
• Zone 6b (261 stations)
• Zone 7a (231 stations)
• Zone 7b (173 stations)
• Zone 8a (165 stations)
• Zone 8b (158 stations)
• Zone 9a (77 stations)

Zones are zone derived from PRISM 2023 grid at the station location (not the official USDA map).