These molds create what is quintessentially a paving stone like any other (these ones are just more aesthetically pleasing) so the cold doesn't affect them any more than standard pavers/patio stones. There is space between the concrete to use pebbles/sand/dirt. There will be some movement, especially as the ground thaws/freezes (and here in Regina that is ALL the time between September and oh...June LOL).

I have a pathmate and intend to redo my patio with them. I used them in Fort McMurray (temperatures there vary from +34C in summer to -48C in winter and they did marvelously so I don't anticipate any problems here.

With a smile,
Deb
Regina, Saskatchewan, Canada