I went to Jack Astor's Bar & Grill at Yonge and Dundas and LOVED it! It gives you an amazing view of the hustle and bustle in Toronto and is affordable to boot :)

Curated list for you! http://www.blogto.com/toronto/the_best_rooftop_patios_in_toronto/

There are MANY great rooftop patios in Toronto but one of my favourites is called The Pilot.

The Porch Toronto is a fan favourite 

Panorama Lounge

My top 5 best patios is in Winston's English Pub & Grill, it’s all about the beer! In O'Shea's Irish Pub, a large rooftop deck with a great downtown location. In Yard & Flagon Pub, it's called the trendy Broadway district. Try also The Hose and Hydrant Brew Pub and Spadina Freehouse, where live music and a sophisticated menu is serve. I hope this can help you!