The cutoff temperature for league games is -25 C, one hour before game time. We don't play at -25, at -24 we do play. We go by the temperature listed on the weather channel, channel 23, the weather network.  Generally this information can also be obtained via the link to the weather network at http://www.theweathernetwork.com/weather/CAYT0019.  Please note though that sometimes the information on the website is not as up to date as that on channel 23.  So, if it is on the cut off line it may be worth confirming with your team rep if the game is on or not.