History of Daylight Saving Time: Why do we Spring forward?

It seems like only yesterday that we discussed the end of Daylight Saving Time, or DST, a brilliant campaign to convince us we’re getting more daylight each day when in reality, they’ve simply changed their clocks and then forgotten about it within two weeks. It was only back in November, four months ago.


Recent Changes in Daylight Saving Time

Indeed, the new rules for DST that began in 2007 meant an extra four or five weeks of DST each year. There are now 238 days of DST, compared to a total of 210 days of DST back in 2006 under the previous rules. This means the U. S. remains on DST for about 65% of the year. So if you think about it, DST will be in effect for most of the year; Standard time is no longer the standard. It might be more significant to recognize Daylight Losing Time.


Starting Daylight Saving Time

DST begins each year at 2:00 a.m. on the second Sunday in March in most of the United States and its territories. However, some places have not bought into this campaign. It is not observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands, nor in Arizona, except for the Navajo Indian Reservation, which does observe DST.

Now: an answer to the age-old question

“Does DST actually save energy?”


Daylight Saving Time Energy Savings?

A Department of Energy study was released in early November 2008, showing that Daylight Saving Time does, in fact, save energy.


Daylight Saving Time Energy

  • The total electricity savings of Extended Daylight Saving Time were about 1.3 Tera Watt-hour (TWh). This corresponds to 0.5 percent per day of Extended Daylight Saving Time or 0.03 percent of electricity consumption over the year. In comparison, the total 2007 electricity consumption in the United States was 3,900 TWh.
  • In terms of national primary energy consumption, the electricity savings translate to a reduction of 17 Trillion Btu (TBtu) over the spring and fall Extended Daylight Saving Time periods or roughly 0.02 percent of total U.S. energy consumption during 2007 of 101,000 TBtu.

How much again? We’re talking two one-hundredths of a percent of annual energy consumption reduced!


How will you spend these energy savings?


Bill Petro, your friendly neighborhood historian

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About billpetro

Bill Petro has been a technology sales enablement executive with extensive experience in Cloud Computing, Automation, Data Center, Information Storage, Big Data/Analytics, Mobile, and Social technologies.


  1. Bill,

    I’ve enjoyed your succinct explanations for years.

    P.S. Please don’t think badly of me for continuing to use AOL. If you must banish me from your cyber sphere, I’ll understand.

  2. SO…. I went out and found a Forbes article listing the average price of energy and they quoting reliable sources estimated $23.31 per Million BTUs as the cost of Electricity. If I plug in your numbers of 17 Trillion BTU saved (17,000 million – check my math please) I get $447.2k in savings….I think the disruption alone in computer programming, reminders announcements everywhere, etc. easily eats that up… I think I will vote to pick one time and stick with it… OR if “they” would like to give me the “savings,” I would consider maintaining the insanity.

    • Tom,

      I think you’re on to something there 🙂


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