USA and Canada Standard Time Date schedules here
The Mountain Timezone is an area 7 hours behind Greenwich Mean Time (GMT-7) during the winter months (referred to as MST) and 6 hours behind Greenwich Mean Time (GMT-6) during the summer months (referred to as MDT). At the moment, the following schedule is used:
From 2 A.M. on the second Sunday in March to 2 A.M. on the first Sunday in November, Daylight Saving Time is in effect. At all other times, Standard Time is in effect.
In most states in the USA and in most provinces in Canada, Daylight-Saving Time (DST) is observed. During DST the time is shifted forward by 1 hour to Mountain Daylight Time (MDT); which is 6 hours behind Greenwich Mean Time (GMT-6).
After the Summer months Mountain Time is shifted back by 1 hour to US Mountain Standard Time (MST) or (GMT-7).