Zone 9b
In USDA zone 9b the coldest night of an average winter reaches 25 to 30 °F (−3.9 to −1.1 °C). 2,085 ZIP codes (5.2% of all) are in this zone.
Frost dates vary within zone 9b
For the middle half of zone-9b ZIP codes the last spring frost falls between Feb 2 and Feb 21, and the first fall frost between Dec 4 and Dec 13. The zone measures winter cold, not season length: humid Eastern and dry Western towns in the same zone can be weeks apart. Use your ZIP code for a planting date.
States with zone 9b
Cities mostly in zone 9b
← Zone 9a (colder)Zone 10a (warmer) →
Questions
What is the temperature range of zone 9b?
Zone 9b covers places where the coldest night of an average winter (the annual extreme minimum averaged over 1991–2020) is 25 to 30 °F, or −3.9 to −1.1 °C.
When is the last frost in zone 9b?
Across ZIP codes in zone 9b, the median last spring frost falls between Feb 2 and Feb 21 for the middle half of places. Zone alone doesn't set the frost date — check your ZIP code.
Which states have zone 9b?
Zone 9b occurs in 10 states; the most ZIP codes are in California, Texas, Florida, Arizona, Louisiana.
What can I grow in zone 9b?
Perennials, shrubs and trees labeled hardy to zone 9b or a lower (colder) number should survive a typical winter. Annual vegetables depend on frost dates rather than zone.
Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.