Zone 9b Frost Dates & Planting Calendar

What zone 9b actually tells you

The 2023 USDA Plant Hardiness Zone Map puts a place in zone 9b when the coldest night of the year averaged 25 to 30°F (-3.9 to -1.1°C) over 1991–2020. The zone says which perennials survive the winter, not when to plant in spring.

Across the 199 NOAA stations behind zone 9b ZIP pages, the median 50% last spring frost is February 15 and the median first fall frost December 6; the last frost alone ranges from January 16 to June 9 from one station to another.

Frost dates answer the planting question, and they are read from the nearest NOAA station, not from the zone. The zone 9b ZIP codes here lie in 10 states; pick your own ZIP code below, or look up the zone of any ZIP code.