USDA Plant Hardiness Zone
Zone 5a Frost Dates & Planting Calendar
2,141 ZIP codes across 20 states fall in zone 5a.
- Zone
- 5a
- Average Annual Low
- -20 to -15°F
- Typical Growing Season
- 141 days
- ZIP Codes
- 2,141
What zone 5a actually tells you
A hardiness zone describes one thing: the average coldest night of the year, which in zone 5a falls between -20 to -15°F. It answers whether a perennial will survive the winter — not when to plant in spring.
Frost dates answer the planting question, and they vary widely inside a single zone. Zone 5a spans 20 states, and a coastal ZIP can differ from an inland one by three weeks despite sharing the zone. Pick your own ZIP code below rather than planting by zone alone.