Daylight Saving Time and Time Zones

    On November 6th, Daylight Saving Time starts, for most of the country at least. This is a hard concept to understand, so I wanted to bring clarity to it. Most of the US, and much of the world, change their clocks twice a year. In the Fall, everyone moves their time back one hour and  then forward one hour in the spring. The saying goes, “Spring Forward and Fall Backward.” Why do we do this?

    This is a concept that was used throughout history by ancient civilizations. The Romans used water clocks and changed weights during different months of the year. Most civilizations would simply adjust their daily routines to utilize the light of the Sun. But the modern use of Daylight Savings Time (DST), versus Standard Time, is credited to Benjamin Franklin. In 1784 he authored an essay entitled, “An Economical Project for Diminishing the Cost of Light”, when he suggested rising earlier to save candles. A number of countries introduced the concept, but was met with resistance, mainly from farmers. Many people resist it even today since we no longer use candles for light.

    Germany was the first country to implement the use of DST on April 30, 1916. It was used to save fuel during WWI. The notion was picked up by England, the US and other countries during the war. After the end of WWI, many countries changed back to standard time.

    The US maintained the use of DST in many states but wasn’t made into a national law until President Franklin D. Roosevelt introduced it during WWII. It was called War Time. Instead of Eastern Standard Time (EST), it was called Eastern War Time (EWT). It was implemented on February 9, 1942, until September 30, 1945. All Year Long for 3 years! The law was enforced 40 days after the attack on Pearl Harbor.

    But this caused major confusion in the US from 1945 until 1966, especially for the travel and broadcasting industry. During those years, states could choose when DST started and ended. To solve the confusion, Congress passed the Uniform Time Act of 1966 that set the time change to begin the last Sunday of April and end the last Sunday of October. The DST schedule was revised several times over the years. The current schedule now follows the Energy Policy Act of 2005. Now DST starts on the second Sunday on March and ends on the first Sunday in November.

    Even though DST is a national law, Arizona and Hawaii opted out of using it. So, when the rest of the country changes their clock twice a year, the residents of Arizona and Hawaii never change their clocks. Since I live in Arizona, that makes it a little tricky for me. During the winter, I’m two hours earlier than the east coast and during the summer I’m three hours earlier. I have to pay attention to when it changes or else I’ll be one hour off with my clients. I call it the two transition weeks of the year. I deal with time zones everyday with my international clients.

    Now let’s look at the abbreviations. There are 24 different time zones in the world, starting at Greenwich England, which is called Greenwich Mean Time (GMT). The time zones start there because that location is at 0 degrees longitude. This system divides the world into 24 different time zones, each  with 15 degrees of longitude. This is based on the concept that the Earth rotates once every 24 hours and there are 360 degrees of longitude. Each hour the Earth rotates 1/24 of a circle or 15 degrees. 15 x 24 = 360.

    Each time zone has a different abbreviation, for example Fiji Time is FJT and Eastern European Time is EET. The US has 4 time zones, Eastern Time (ET), Central Time (CT), Mountain Time (MT) and Pacific Time (PT). During the summer, they are called EDT, CDT, MDT and PDT, or Eastern Daylight Time, Central Daylight Time, Mountain Daylight time and Pacific Daylight time.

    I often see postings that meetings begin at 3pm EDT and Noon EST, which is incorrect. We are all on Daylight Time or Standard Time at the same time, except for Arizona and Hawaii, of course.

    This is where time and space meet…


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