Certainly true, Ken, that temperature/zones don't follow lines of latitude. Alaska covers zones 1 through 7b according to the US National Arboretum:
http://www.usna.usda.gov/Hardz...
I grew up in the UK and gardened there in the equivalent of USDA Zone 8-9, then moved south to Ontario, Canada (roughly same latitude as southern France) and dropped to zone 4!
