Why don't you put an overlay of major freeways on your map, since zip codes can be very large areas, encompassing many zones. To go by zip code it not effective and without some type of overlay on the map it's impossible to pin point my area on your map. Basically, you system here is 100% ineffective.

Climate zones are like earthquake zones: There are no clear lines because they are zones.

Using your zipcode puts you in the ballpark then you have to narrow it down to suit your yard. Influences will be the direction your yard faces, overhead trees, amount of pavement, mountains, rivers, etc. Using a road map would be exactly the same - you would still have to tweek to fit your circumstances.

Hi Russ and welcome. The zone map is put out by the USDA not by us. Try this map and mouse over your area to enlarge http://garden.org/nga/zipzone/...

It's really intended for use by farmers anyway and is not all that effective for home gardeners because there are too many variables that have an effect on what zone your garden is. The Sunset zones are much more useful for gardeners (but still not perfect) http://www.sunset.com/garden/c...

For example, when I lived in Utah, the whole Salt Lake valley was designated USDA zone 5 on the map. The front yard of our house (facing north) was zone 5 but a large area right near the house in the back yard (facing south) was at least two zones warmer, and I could overwinter a lot of plants there that would freeze and die out front.

Another example, if you look at the USDA map, zone 8 stretches just about all the way around the edges of the continent, up into the Pac. Northwest and down into Florida. Well I am originally from the Pac. Northwest and now live in Florida and it's for sure not the same for gardeners there in winter. Sure it never gets below a certain temperature in winter, because the massive Pacific Ocean keeps it warmer than anywhere else that far north. But it's also cold and grey and wet during the days with very short daylight and weak sunshine if you ever see it, completely unlike zone 8 in Florida where we can grow a lot of stuff all winter, and just need to keep some frost protection handy for a few cold nights here and there.

Hi & welcome, Russ!

What question did you come to this site to answer, that was left unanswered by your peek at the zone map? A philosophical discussion about garden zones is probably not what you seek.

RussM,
The USDA climate zone map is just a guide. Each person/property can have micro-zones that differ. In my yard I have seen anywhere from zone 8a to 9b depending on exactly where something is planted.

May I inquire what is your zip code/state/city? There are places you could get more accurate information for your exact location such as your local County Cooperative Extension Service or a local farm/feed store, but not knowing your location I cannot give you more details.