Probably anywhere around this time. My friend lives in Toronto and goes to Montreal every May long weekend. That's when the city goes crazy on partying at all the clubs and I'm sure the weather there is nice. Not to mention, you get to see the nice flowers and scenery in Old Montreal.
I went in March with
GFunk. Have a look at some of the
pics and check out some other threads regarding Montreal
here and
here. Have fun!