The Mountain Time Zone of North America keeps time by subtracting seven hours from Coordinated Universal Time, sometimes called Greenwich Mean Time -LRB- UTC-7 -RRB- during the shortest days of autumn and winter, and by subtracting six hours during daylight saving time in the spring, summer, and early autumn -LRB- UTC-6 -RRB-.
The Mountain Time Zone subtracts seven hours from UTC during standard time -LRB- UTC-7 -RRB- and six hours during daylight saving time -LRB- UTC-6 -RRB-.