Just a few links that were interesting :

An interactive version of the map, where you can zoom in and see the details of the zones here.

Half-way through this article is more information about how the map was created.

The old 1990 version for reference of changes.

Another old version if you want to get even more confused:

Also, my main gardening website is down. I spend several days getting it all fixed up, only to come back to it and have it not working again. This is frustrating, because I haven’t touched it in the meanwhile. The blog seems unaffected luckily. In many ways I don’t care: this year is turning into a sabbatical from gardening work. With a baby coming and less family around to help out with the other kid, that’s fine by me. If I don’t post here that regularly, just know I’m enjoying kids and focusing on other things.