Smoke - Due to numerous fires in Alberta, northern Saskatchewan and northern BC, there was much more smoke than usual this May. The vast majority of the smoke remained above the surface, which gave cloudier skies and could not be smelled at the surface. I counted at least 8 days with smoke aloft in Winnipeg (possibly a few more - I wasn't watching extremely closely every single day). It occurred mostly in the period of the 14th to 23rd. In the ECCC Archives, we had the first mentions of smoke in the hourly observations in May since 2002. There were also 6 days with smoke causing a reduction in visibility at Winnipeg Airport.
Rapid green-up - Due to a very cold April followed by a very warm May, the spring green-up was remarkably fast. May started with little to no green grass or budding trees, but then the trees were mostly fully leaved by the May Long Weekend.
Thunderstorms - Note that other parts of the city, particularly in the south, had up to 4 thunderstorm days this May: May 10, 27, 29 and 30. Beausejour received one of the heaviest downpours of the month in Manitoba. On May 30, the town received 43.8 mm of rain in 1 hour (mb ag station) along with a wind gust of 82 km/h. Streets flooded in the town.
Note that other parts of the city received more precip, particularly due to more rain in May. Between 60 and 70 mm fell in some other areas.