Regina's new Mosaic stadium was designed to reduce wind, but its shape can make the wind particularly unpredictable.
The stadium is designed to block the cold northwest winds that tear through the Prairies, bringing a chill even in the dog days of summer.
Before the stadium was built, wind studies for the building were done, says Rod Schmidt, the manager of stadium development.
"Part of our requirements was that the wind needed to be reduced by certain percentages on the field of play and in the stands," said Schmidt.
"Part of the process was having our design team take the stadium design through comprehensive testing. There was an organization called RWDI that actually did wind tunnel testing or computer testing of the venue."
When winds hit the closed off northwest side of the stadium they are forced over top of it and around the sides. This means the north end zone stays sheltered.
But, after those winds travel around and over the stadium, they curve and swirl.
"It's just like a car driving: you get that wind coming around it and in the back behind the vehicle the wind is swirling around so we see that same kind of effect," said Doug Charko, a meteorologist who works with security at Mosaic Stadium and provides weather forecasts for game day.
Because the south side of the stadium is open, those curving winds can rush into the stadium around the scoreboard.
What does that mean?
Even if aloft you're seeing a northwest wind from the air passing over the stadium, at the field level the wind may be howling in the opposite direction — from the south.
That kind of situation doesn't happen all the time, but if the speed and direction are just right, it can have a drastic effect on the players on the field. This was the case during the Labour Day Classic: winds on the north side of the field were relatively light but on the south side they were rushing in from south at the surface.
A similar reverse surface wind can happen on the north side of the stadium if a strong southerly wind is in place. The wind travels in the open side of the stadium, striking the seats at the north side and travelling back along the field to the south.
The winds are stronger outside of the stadium, too.
Game day at Mosaic Stadium doesn't begin at kickoff. Rider fans flock to Confederation Park beforehand for some pre-game celebrations.
Winds can howl through Confederation Park on a breezy day due to stadium physics.
"The oval shape of the stadium results in a compression of the wind on either side," said Charko. "So the way the walls are shaped, the wind is funneled into narrow points in effect. So on the east and west side in a strong north/northwest wind where it's 20 or 30 km/h, in general it could be 40 or 50."
What about the vents?
If you have been in the stadium on a hot summer's day, you may have seen vents open around the stadium.
Though they may seem like a way to regulate the wind, they are actually used to moderate the stadium's temperature.
"In the summertime, heat ... goes to the top of the building and is held in by the roof," said Schmidt. "So the vents are opened, air comes in through those, pushes along the bottom of the roof and helps take that hotter air out of the building. So it does have a minor air conditioning effect."
What do the pros think?
Tyler Crapigna, the Roughriders' kicker, thinks the stadium's design has helped reduce the wind when compared to the old stadium.
"It swirls a little bit at the end zone there with the scoreboard but other than that it's a pretty predicable wind," said Crapigna.
"The worst [end zone] would probably be the scoreboard end zone. I mean, that's the most open one and the wind is just coming in through there, funneling through."
Josh Bartel, the punter for the Riders has noticed more variability with the stadium's wind.
"It sort of changes every 15 yards the wind ... but, you know, you just got to get a nice tight spiral and try and get it through that wind," he said.