use a search engine and type in USDA zone and it should bring up all the info you need from from zip code once you get to the site

Since you at the GardenWeb site, just go to "Tools & Directories" at the top of the page and choose "Zone Finder." You just type in your zip code and your zone is identified.

I have found that different websites will respond with different zones if you are near the border of 2 zones as I am. Some of the zone finders return zone 8 and others zone 9. (My office zip code returns zone 9 on all that I have tried.) So, if I have a plant hardy to zone 8, I make sure I give it plenty of water during the summer. Conversely, those hardy to zone 9 receive a little more consideration during the winter months -- I'm more likely to cover in time.