What planting zone am I in?
Last checked
Your planting zone is a shorthand for how cold it gets where you live. It tells you which plants will survive a normal winter outdoors. You can look up any address on the hardiness map.
What does the zone number mean?
It describes the average coldest night of the year. Zone 5 is colder than zone 6, and each zone step is about 10°F of difference. The letters split each zone in half: 7a is the colder half of zone 7, 7b the milder half.
When a plant label says “hardy to zone 6,” it means the plant should survive a typical winter in zone 6 and anywhere milder.
Why does my neighbor have a different zone?
Because cold does not respect property lines. Zones follow terrain, and terrain changes fast.
Cold air sinks, so the bottom of a valley can be a full zone colder than the slope above it. Large bodies of water hold heat and keep nearby land milder into the winter. Cities are warmer than the countryside around them, sometimes by a whole zone, because roads and buildings store heat.
Did the zones change recently?
Yes. The USDA updated the map in 2023 and about half the country shifted, most of it half a zone warmer.
That matters if you are working from an old reference. A plant guide printed before 2023, or a garden centre label that was never updated, may be describing a zone your address no longer sits in.
Does a warmer zone mean I can grow anything hardier?
Not quite, and this is where the zone system gets over-trusted.
Zones only describe winter cold. They say nothing about summer heat, humidity, rainfall, soil, or how long your growing season is. Two places in the same zone can be completely different to garden in — one dry with cool nights, the other humid with brutal summers. The zone tells you what will not freeze to death. It does not tell you what will thrive.
What about the last frost date?
That is a separate question, and usually the more practical one. The zone tells you what survives the winter; the frost date tells you when it is safe to plant out in spring.
The two are related but not interchangeable. A late spring frost can kill a plant that is perfectly hardy for your zone, simply because it went in the ground two weeks early.
Why is this on a house-hunting map?
Because for some people it is a real criterion, and it is almost impossible to see from a listing.
If you want to grow citrus, keep bees, run a market garden, or simply not lose the plants you are bringing with you, the zone constrains where you can go. It is also a fast sanity check when comparing two metros that sound similar: a one-zone difference is a genuinely different garden.
It pairs well with other layers. Put hardiness next to green space if you are after somewhere to grow things with room to walk.
Where does the data come from?
The USDA Plant Hardiness Zone Map, shown as published. It updates on a multi-year cycle rather than annually, and the page carries the date we last checked it.
Look up your zone, or anywhere you are thinking of moving, on the map. It is free.