In the graph below you see the time zone difference between Mountain Daylight Time and Eastern Standard Time. Drag the bubble to adjust the time and to see the corresponding time in the other time zone.
Mountain Daylight Time is the time zone of the US and Canadian states around the Rocky Mountains, including cities like Edmonton, Calgary, Denver and Salt Lake City. Eastern Standard Time is the time zone of the Canadian and US East Coast, with places like Montreal, Ottawa, New York, Washington D.C. And Miami.
Usually it is preferable to schedule meetings in the morning for the person in MDT and after lunch for the person in EST.
MDT is observed in the Western part of central US and Canada, as well as the North West corner of Mexico. It is 6 hours behind UTC and turns into MST in the summer. In Mexico, this time zone is known as Zona Pacifico (Pacific Zone). The name Mountain Daylight Time comes from it covering the Rocky Mountains in Western United States.
In the US, Arizona, Colorado, Montana, Utah, New Mexico and Wyoming are all observing Mountain Daylight Time but there is also a bunch where part of the state observe MDT and part another time zone, like CDT or PDT.
MDT is observed in parts of Canada, the US and Mexico. The only province in Canada to be fully covered by MDT is Alberta whereas other provinces like British Columbia and Northwest Territories are split between MDT and PDT.
In Mexico, it is only the states in the north western corner of the country, including Baja California, Sinaloa and Chihuahua that observe MDT.
The largest city observing Mountain Daylight Time is Phoenix, followed by Denver and El Paso/Juarez.
MDT is observed in almost all locations that observe Mountain Time, except the states of Arizona (US) and Sinaloa (Mexico). DST is in effect between March and November and adds one hour time difference to UTC.
This is the standard time of the Eastern US, Canada and parts of the Caribbean. It is in most places observed only in the winter months, from November to March. The origin of EST is the same as for most time zones – it was introduced when the railroad was built across the United States. It is important to note that there is also Eastern Standard Time in Australia, but this is usually called AEST and thus not to be confused with EST.
Most of the Eastern seaboard of the US observe EST, as well as most locations in Eastern Canada although there are a few exceptions. Locations such as New York, Washington, Quebec and Ontario are all on Eastern Standard Time. Also some Caribbean locations such as Jamaica, Haiti and Panama are in this time zone.
It is important to note that with the exception of Panama, Jamaica and a couple of locations in Canada and the US most in this time zone do observe DST and thus switch to EDT in the summer. As always, it is better to look up the actual location than the timezone itself.