We've spend 2 weeks in British Columbia seven years ago (high summer, high temperatures, very low humidity).
Wonderfull, we had booked a fly and drive arrangement with lots of outdoor activities paid upfront (so you do them) and we stayed at small B&B's and cabins in Natural parks. One of the best holidays we had. Started and ended in Vancouver, halfway through we drove the famous 'gletcher route' from Banf to Jasper. On our second evening (after we spend the whole day from Victoris Island on a whale-watching boat and ended right in the middle of a group of moer then 30 Orca's ! !) in Vancouver there was a hugh firworks display on music, never seen anything like it.