I'm thinking it's August 8th, which is "Wasagaming Chamber Days" (
https://discoverclearlake.com/events/wasagaming-chamber-days/).
The des:cription says "Fun family activities, entertainment, a parade and much more", but that the schedule will be posted when available.
I can't recall for sure if Chamber Days is the same weekend they usually host the concert or not, but it's usually in August so the timing is right.
Edit: I don't think it's that weekend after all - looking into past chamber days, it doesn't look like there has been a concert. So I don't know either.
Edit again: Found some mention of it, at least, on the government page:
http://www.pc.gc.ca/en/pn-np/mb/riding/activ/activites-events
"TBD Canada 150 Free Concert"
So it doesn't appear to be confirmed at this point.
Edited by pudds, 2017-07-06 16:12:50