Mountain Standard Time (MST) and Eastern Standard Time (EST) are two of the four main time zones in the contiguous United States. Understanding the difference between them is crucial for scheduling calls, meetings, and travel. This article clarifies the difference between MST and EST, including how Daylight Saving Time affects them.
Understanding Mountain Standard Time (MST)
MST is 7 hours behind Coordinated Universal Time (UTC-7). It’s observed in several states, including:
- Arizona (most of the state does not observe Daylight Saving Time)
- Colorado
- Montana
- New Mexico
- Utah
- Wyoming
Parts of Idaho, Kansas, Nebraska, North Dakota, Oregon, South Dakota, and Texas also observe MST.
Understanding Eastern Standard Time (EST)
EST is 5 hours behind Coordinated Universal Time (UTC-5). It’s observed in a larger number of states along the eastern seaboard, including:
- Connecticut
- Delaware
- Florida (most of the state)
- Georgia
- Indiana (most of the state)
- Kentucky (eastern part)
- Maine
- Maryland
- Massachusetts
- Michigan
- New Hampshire
- New Jersey
- New York
- North Carolina
- Ohio
- Pennsylvania
- Rhode Island
- South Carolina
- Tennessee (eastern part)
- Vermont
- Virginia
- West Virginia
The Two-Hour Difference
The key difference: MST is two hours behind EST. When it’s noon in New York City (EST), it’s 10:00 AM in Denver (MST).
Daylight Saving Time (DST)
Both MST and EST observe Daylight Saving Time, shifting the clock forward one hour during warmer months. During DST:
- Mountain Time becomes Mountain Daylight Time (MDT), UTC-6.
- Eastern Time becomes Eastern Daylight Time (EDT), UTC-4.
The two-hour difference between the time zones remains the same during DST. However, Arizona is a notable exception. Most of Arizona does not observe DST, remaining on MST year-round.
Practical Implications of the Time Difference
The two-hour difference can significantly impact scheduling across time zones. Consider these scenarios:
- Business Meetings: When scheduling a meeting with participants in both MST and EST, be mindful of the time difference to ensure everyone joins at the correct time.
- Travel: Adjust your schedule accordingly when traveling between MST and EST zones to avoid confusion and missed appointments.
- Phone Calls: Remember the time difference when making calls across time zones, especially for time-sensitive matters.
- Broadcasts: Live television broadcasts, sporting events, and other scheduled programs will air at different local times in MST and EST.
Calculating Time Conversions
To convert from MST to EST, add two hours. To convert from EST to MST, subtract two hours. Be sure to account for DST if applicable.
Conclusion
Understanding the two-hour difference between Mountain Standard Time (MST) and Eastern Standard Time (EST) is essential for effective communication and scheduling across these time zones. Remembering the impact of Daylight Saving Time, particularly Arizona’s unique situation, will help avoid confusion and ensure smooth interactions.
