Time Zones
Time Zones
- www.timeanddate.com
- a great resource for time zones, DST and other time related items.
- Time Zones & GMT/UTC/Zulu - Example of converting from Time Zone to UTC.
- Eastern Time Zone - ET - (ex: Atlanta, GA)
- EST (Eastern Standard Time) - add 5 hours to get UTC time.
24hr clock: 8:00 EST = 13:00 UTC
- EDT (Eastern Daylight Savings Time) - add 4 hours to get UTC
time.
24hr clock: 8:00 EDT = 12:00 UTC
- Central Time Zone - CT - (ex: New Orleans, LA)
- CST (Central Standard Time) - add 6 hours to get UTC time.
24hr clock: 8:00 CST = 14:00 UTC
- CDT (Central Daylight Savings Time) - add 5 hours to get UTC
time.
24hr clock: 8:00 CDT = 13:00 UTC
- Mountain Time Zone - MT - (ex: Phoenix, AZ)
- MST (Mountain Standard Time) - add 7 hours to get UTC time.
24hr clock: 8:00 MST = 15:00 UTC
- MDT (Mountain Daylight Savings Time) - add 6 hours to get UTC
time.
24hr clock: 8:00 MDT = 14:00 UTC
- Pacific Time Zone - MT - (ex: San Francisco, CA)
- PST (Pacific Standard Time) - add 8 hours to get UTC time.
24hr clock: 8:00 MST = 16:00 UTC
- PDT (Pacific Daylight Savings Time) - add 7 hours to get UTC
time.
24hr clock: 8:00 MDT = 15:00 UTC
Daylight Savings Time (DST)
- Clock change: Spring forward, Fall back. So in the Spring clocks
go from 2:00am to 3:00am and in the Fall from 2:00am to 1:00am
- US Exceptions:
- No time change: Hawaii, American Samoa, Guam, Puerto Rico, the
Virgin Islands, and Arizona.
- The Navajo Nation participates in the Daylight Saving Time policy,
even in Arizona, due to its large size and location in three states.
- Time change rule
- 2007 - On 08/08/2005, President George W. Bush signed the Energy
Policy Act of 2005
- US
- Starts: 2:00am on the second Sunday in March
- Ends: 2:00am on the first Sunday in November
- Time changes differently based on the time zone.
- DST (start & stops)
2008: 03/09/2008 thru 11/09/2008
2007: 03/11/2007 thru 11/04/2007
- European Union
- Starts: 1:00am (Universal Time - Greenwich Mean Time (GMT))
on the last Sunday in March
- Stops: 1:00am (Universal Time - Greenwich Mean Time (GMT))
on the last Sunday in October
- All times change at once based on the GMT time
- Each country can have it's own rules.
- Before 2007
- Starts: 2:00 a.m. on the first Sunday of April
- Ends: 2:00 a.m. on the last Sunday of October.
- Computer Issues
- OS Systems - obtain a patch so that the computer changes it's time
correctly or you will need to change it manually.
- Applications, Data in DB Systems and GMT
- Data is normally stored as a GMT (Greenwich Mean Time) or UT
(Universal Time) time.
- Handheld Devices (PDA, etc...) - install a patch or just change it
manually.
- Watches - change it manually.