The Lethbridge Fish & Game Association has one of the best ranges I've ever shot at and it has full trap and skeet facilities. Check out their website.
Skeet seems to be more popular with the club and they frequently shoot trap between rounds on the weekends.
Use of the equipment is limitted to club members and arrangements would need to be made in advance. It's not a drop in and shoot some trap setup, but there's also archery, 400m rifle, and several pistol ranges for use.
I don't see a lot of trap shooters during the winter, but there are lots in the summer and fall.