How to Read USDA Hardiness Zones
USDA zones indicate the coldest winter temperature in your area. They help you choose perennials that survive winter, but not annuals or planting dates.
Zones are about winter survival, not growing season.
The Zones
| Zone | Min Temp | Example |
|---|---|---|
| 3 | -40 to -30°F | Minneapolis |
| 4 | -30 to -20°F | Denver |
| 5 | -20 to -10°F | Chicago |
| 6 | -10 to 0°F | St. Louis |
| 7 | 0 to 10°F | Virginia |
| 8 | 10 to 20°F | Dallas |
| 9 | 20 to 30°F | Houston |
| 10 | 30 to 40°F | Miami |
| 11 | 40 to 50°F | Hawaii |
What Zones Tell You
- Perennials: Will they survive winter?
- Shrubs/trees: Will they survive?
- Not annuals: They die each year anyway.
- Not planting dates: Use last frost date.
What Zones Don’t Tell You
- Last frost date
- First frost date
- Summer heat
- Rainfall
- Microclimates
Common Questions
How do I find my zone? USDA map. Enter zip code.
Do zones matter for vegetables? Mostly no. They’re annuals.
What’s a microclimate? A small area with different conditions.
Can I grow outside my zone? Yes, with protection.
What about UK/Europe? Different systems. RHS zones for UK.
Do zones change? Yes. Updated in 2023.