USDA hardiness zone 13a
USDA plant hardiness zone 13a covers areas whose average annual extreme minimum winter temperature is — — the standard USDA measure of which perennials survive an average winter. Hardiness zone sets winter survival, but planting DATES depend on your local frost calendar, which varies within a zone. 3 locations on this site fall in zone 13a (Culebra, PR, Kaneohe Base, HI, San Juan, PR); open one to see its frost dates, growing-season length, and a printable per-crop planting calendar.
Locations in zone 13a
| Location | Last frost | First frost | Season (days) |
|---|---|---|---|
| Culebra, PR | Mar 13 | Nov 30 | 262 |
| Kaneohe Base, HI | frost-free | frost-free | 365 |
| San Juan, PR | frost-free | frost-free | 365 |
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
What zone 13a means for your garden
A plant rated "hardy to zone 13a" can be expected to survive a winter whose coldest night lands in the — range — the metric the USDA map is built on. That governs perennials, shrubs, and trees. For annual vegetables, what matters is the frost calendar: the dates of the average last spring and first fall freeze, which set when it is safe to plant and how long the season runs. Those come from the individual location pages above.
Zones are from the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP — see the methodology page. Browse all hardiness zones or crop-by-crop timing.
Frequently asked questions
- What temperature range is USDA zone 13a?
- Zone 13a covers areas whose average annual extreme minimum winter temperature is —. Each numbered zone is a 10°F band; the "a" and "b" half-zones split it into 5°F steps.
- Does zone 13a tell me when to plant?
- No — the hardiness zone tells you which perennials survive winter, not when to sow annual vegetables. Planting dates depend on your local last and first frost, which can vary within a single zone. Open one of the sample locations in zone 13a to see its frost calendar and per-crop planting windows.
- What can I grow in zone 13a?
- Almost any common vegetable can be grown in zone 13a; what changes with zone and local climate is the timing and the length of the season. Cold-hardy crops (peas, spinach, lettuce) go out earliest, tender crops (tomatoes, peppers, basil) after the last frost. Use each location's calendar for exact dates.