The temperatures in the Banff area in March should be compared to the temperatures of any ski areas in the country during March. --You just need to make sure you compare similar types of terrain.
Above treeline skiing in the Banff region generally occurs around the 7500ft. altitude, where above treeline skiing in Colorado generally occurs well into the 11,000ft. altitude. Both of these areas can be really cold during March or any other time of the mid-winter season. -- Don't expect this high altitude environment to be 'balmy' during the transition to springtime conditions.
With that said, I consider the Banff area to be very tolerable during March. Just remember to look at the trail map and remember that skiing at 8000ft. altitudes will possibly give you weather conditions that are about the same as the top of Colorado's highest ski areas. .... But then, you still have Mother Nature rolling the dice, and any type of weather could be had!
My rule of thumb is that Canadian Rocky Mountain skiing is too cold for me during the last three weeks of January and the first three weeks of February. The rest of the season, I consider it to be paradise for any of us southern boys. [img]smile.gif[/img]