I grew up in Calgary. One year it snowed on the last day of school, which in Calgary is June 30. A couple of years later it snowed on the first day of school, which if I recall was August 29.
Summer vacation for Canadian schools is only two months -- July and August. You can see why.
I've heard stories about the short summer in Canada. July is really the peak heat period in Pocatello. I really like the Spring and Fall. Mostly shirt sleeve whether without extremes.