Compare Two Hardiness Zones
Gardeners compare zones all the time: I moved from zone 6 to zone 8, what changes? Pick any two zones and see them side by side, with the winter low bands, frost windows, and growing seasons from our zone data, and a plain summary of what gets easier and what gets harder moving from the first zone to the second.
Zone 6 and zone 8 side by side
Winter lows: zone 8 runs about 20 °F warmer than zone 6 (10 to 20 °F against -10 to 0 °F). Everything rated hardy to zone 6 still survives winter in zone 8, and plants rated for zones 7 to 8, a gamble or a loss in zone 6, become reliable in the ground in zone 8.
Season length: the typical frost-free season grows from about 175 days to about 231 days, about 8 weeks longer. The last spring freeze comes about 5 weeks earlier and the first fall freeze about 3 weeks later, so heat-loving plants get the long warm run they need.
The trade: winter chill shrinks as zones warm up. High-chill fruit that crops well in zone 6 can bloom poorly in zone 8 for lack of cold hours, tender plants stop needing winter protection, and summer heat, water demand, and humidity disease pressure move up the list of problems to manage.
| Measure | Zone 6 | Zone 8 |
|---|---|---|
| Winter low band | -10 to 0 °F (-23.3 to -17.8 °C) | 10 to 20 °F (-12.2 to -6.7 °C) |
| a / b halves | 6a -10 to -5 °F / 6b -5 to 0 °F | 8a 10 to 15 °F / 8b 15 to 20 °F |
| Where it occurs | The Ohio Valley, the Mid-Atlantic, and the lowland Pacific Northwest. | The Southeast coastal plain, the Gulf Coast, much of Texas, and the Pacific Northwest coast. |
| Representative places | Chicago, Illinois; Indianapolis, Indiana; and Spokane, Washington | Charlotte, North Carolina; Atlanta, Georgia; Portland, Oregon; and Dallas, Texas |
| Last spring freeze, typical | Apr 25 (middle half of ZIPs: Apr 19 to May 2) | Mar 24 (middle half of ZIPs: Mar 15 to Mar 31) |
| First fall freeze, typical | Oct 19 (middle half of ZIPs: Oct 13 to Oct 24) | Nov 10 (middle half of ZIPs: Nov 5 to Nov 16) |
| Frost-free season, typical | 175 days (middle half of ZIPs: 163 to 186) | 231 days (middle half of ZIPs: 220 to 244) |
| What grows well | Oaks, lilac, panicle hydrangea, and ninebark over the zone 5 anchors, with four season foundation plantings in the East | Live oak, southern magnolia, laurel oak, and crape myrtle, with azaleas and camellias underneath in the South |
| Yards on YardShare | 354 | 368 |
| Zone guide | Read the zone 6 guide Browse zone 6 yards | Read the zone 8 guide Browse zone 8 yards |
Not sure which zones to compare? Look your own zone up by ZIP code first, then compare it with the zone you are moving to, or the one your plant label keeps mentioning.
How to read the frost rows: the dates and season lengths are medians across every covered ZIP in the zone, from NOAA 1991 to 2020 climate normals, and the middle half of ZIPs in the zone falls in the range shown. A zone is a winter low band, not a frost date band, so the spread inside one zone is wide; use the ZIP lookup for your own planting dates. Zones 10 to 12 have no typical freeze, so they print that instead of a date. Bands and places: 2023 USDA Plant Hardiness Zone Map (USDA and PRISM Climate Group, Oregon State University). What grows well: the YardShare zone plant palettes, sourced from university extension publications.