The only areas you can grow them (with some success) in BC is the Oak Bay area of Victoria and downtown Victoria, there is a rather large Mexican Fan Palm outside of Victoria city hall for example.
Record low temps in areas such as Oak Bay are only around -10 degrees C, and in fact some of these areas can go an entire winter some years without a freezing temperature (again, this is only a very small area within greater Victoria near the coastline).
Anyways, I was in Victoria last month and here are some very nice looking Windmill palms from Beacon Hill Park downtown:
And here is a smaller one in the Harbour
Pics are my own:
http://www.flickr.com/photos/30634635@N03/page2/