Zalfein is Saskatchewan and Alberta running same times right now?
For the summer, Regina, Saskatchewan is CST and Calgary, Alberta is MDT , they are both GMT minus 6. Same time.
In the winter, Saskatchewan is still going to be CST and Alberta is going to be MST, 1 hour difference.
The problem is, Saskatchewan is an exception. In the U.S., people will think you're talking about Central time with Daylight Saving Time, which is 1 hour with Alberta.
So, your event is:
9pm (21:00) PDT (example California), MST(example most of Arizona)
10pm(22:00) MDT(example New Mexico, Colorado, Alberta), CST(example Saskatchewan)
11pm(23:00) US Central time CDT (example Texas)
12am (00:00) Eastern (example New York, Montreal)
4am (04:00) GMT
8am (08:00) Moscow
Zalfein