In accord with heathfield's post, be aware that February and March are the most active months for Chinook winds. All along the Front Range of the Rockies, extremely high winds can occur. They blow from the west-southwest and can reach 100 mph. The winds cause rapidly increasing temperatures due to the compression of the air falling off the nearby mountains. Therefore, one can experience an extremly cold night... say -10F and by sunrise, if the winds have kicked up, see the temprature climb to 50 or 60F. All in all, March is probably the most changeable month of the year...