USDA hardiness zone 13b
In zone 13b, the average annual extreme minimum temperature is 65 to 70°F (18.3 to 21.1°C), based on 1991–2020 data from the 2023 USDA Plant Hardiness Zone Map.
What zone 13b means for your garden
A plant labeled "hardy to zone 13b" should survive a typical winter low of 65°F. Tropical and subtropical plants are an option, but many temperate fruit trees may not get enough winter chill. Zone 13a is the colder half of zone 13.
ZIP codes in zone 13b: 26 in Puerto Rico. New to zones? Read how to read your hardiness zone.
Frost dates in zone 13b
No major city on this site is in zone 13b. At NOAA stations in this zone a 32°F frost is rare (estimate: frost rare at 3 NOAA stations).
Planting calendar for zone 13b
| Crop | Planting windows (frost-free climate) | |||
|---|---|---|---|---|
| Tomato | Jan 15 – Mar 31; Aug 1 – Sep 15 | |||
| Pepper | Feb 1 – Apr 15; Jul 15 – Aug 31 | |||
| Lettuce | Sep 15 – Feb 15 | |||
| Green Beans | Feb 15 – Apr 30; Aug 15 – Sep 30 | |||
| Sweet Corn | Feb 15 – Apr 15; Aug 1 – Aug 31 | |||
| Zucchini & Summer Squash | Feb 15 – Apr 15; Aug 1 – Sep 15 | |||
| Cucumber | Feb 15 – Apr 15; Aug 1 – Sep 15 | |||
| Carrot | Sep 1 – Feb 28 | |||
| Onion | Oct 15 – Jan 15 | |||
| Potato | Jan 1 – Feb 28; Sep 1 – Oct 15 | |||
| Basil | Mar 1 – Jun 30; Aug 15 – Sep 30 | |||
| Spinach | Oct 1 – Feb 15 | |||
| Kale | Sep 1 – Feb 15 | |||
| Broccoli | Sep 1 – Jan 15 | |||
| Peas | Oct 1 – Jan 31 | |||
| Eggplant | Feb 15 – Apr 30; Jul 15 – Aug 31 | |||
| Cabbage | Sep 1 – Jan 31 | |||
| Radish | Sep 15 – Mar 15 | |||
| Strawberry | Oct 1 – Nov 30 | |||
| Beets | Sep 15 – Feb 28 | |||
Where zone 13b occurs
None of the 512 major cities on this site sits in zone 13b. It occurs mostly in thinly populated areas (ZIP codes: 26 in Puerto Rico).
Zone 13b questions
How cold does it get in zone 13b?
Zone 13b is defined by an average annual extreme minimum temperature of 65 to 70°F (18.3 to 21.1°C) for 1991–2020 — the average of each year's single coldest night, not the record low. Individual winters can be colder, so plants rated exactly for zone 13b carry some risk in a severe year.
Does zone 13b get frost?
Rarely. Estimate: frost rare at 3 NOAA stations. Gardens in zone 13b are planted by season and heat rather than by frost date.
Which states have zone 13b?
The 2023 listings put 26 ZIP codes in zone 13b, spread over 1 states and territories. The most are in Puerto Rico (26).
Did zone 13b grow on the 2023 map?
Yes: 11 ZIP codes were in zone 13b on the 2012 map and 26 are on the 2023 map (+15). Of today's zone 13b ZIP codes that were also listed in 2012, 77% were in a colder zone then, 23% were already 13b, and 0% were in a warmer zone. What changed in 2023.