What type of clothing should I wear in Toronto, Canada?

I am going from June 16th until June 26th and the forecast says that it will be about 77 degrees farenheit for that week. I live in Arizona, so I am used to hot climates, wearing shorts and tanktops 24/7, but I am just wondering what I should start packing for my trip. Jeans to Shorts ratio, long sleeves vs. short. Sweatshirts. Anything would help. Thanks!
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I also snowboard every weekend (well not now, its summer) but I go up to colorado so I am used to cold weather as well. So will it be more like Arizona in the Winter or Colorado in the Spring?