The forecast is a bit late due to the recent 2 day chase state side(a post on that to come) but here is the June 2015 forecast for Alberta, Saskatchewan, and Manitoba.
Due to drought the month of May finished off near to colder than normal over all but the NW part of Alberta, where it was much warmer than normal.
Precip wise May 2015 was one of the driest in decades. The drought lead to overnight lows being 3-5C colder than normal and thus even the warmer than normal highs did not do much to cancel that out.
This “cold night” regime will pay a part in the June 2015 conditions.
Overall near normal in the two eastern Provinces, Warmer to much warmer than normal in Alberta. These will likely be the result of very hot weather with cold nights due to the continuation of drought. Due to some gulf flow isolated areas may see more flash floods due to thunderstorms. Showers and thunderstorms look to make up roughly 95% of the rainfall.
June 1-10: warm to very warm. the odd thunderstorm but otherwise very dry. Alberta may get some decent rain, but nowhere near what is needed.
June 10-20: hot and humid briefly in southern Sask and Man. Cooler and dry in Alberta.
June 20-30: Very hot at times with highs in the low to high 30s, Possibly a 40C or two getting out of BC and into Alberta. Humidity below 10% in Alberta, risk of dust storms and a return of extreme fire risk. higher humidity to the east should spark plenty of thunderstorms.