Sunday, October 29, 2006

Making Sense of Day Light Savings Time

Folks in US would have gotten an extra hour of sleep today as the country rolled back the clock by an hour 2:00 AM last night ending the daylight savings time. I have heard many explanations for this bi-annual ritual, but none really made sense.

To add to the mystery, US congress has decided to extend the Daylight Savings by a month from next year, by commencing early and ending in November, past the Halloween weekend. So, in 2007 Daylight Savings Times will begin on March 11 and end November 4 (as compared to April 2 and October 29 in 2006)

Till I was in US, this change never really affected me, but now that I am in India, I am feeling the impact of this switch. Actually, I will start feeling the impact of this switch from tomorrow as I start taking my regular conference calls with my colleagues in US, which will stretch one more hour in to the night.

Generally, most of my calls with US colleagues are done between 8:00 AM - 11:00 AM ET which was 5:30 PM - 8:30 PM till Friday and now it is 6:30 PM - 9:30 PM. Now here is another challenge we run in to.. trying to find a suitable time zone for conference calls with folks in India, China, Australia, Germany & US. I hear you saying.. Welcome to the flat world..!!!!

When do you take your International Calls? Which time zone do you guys go by?


  1. Get a Life.
    Quit your job.
    Get a job that is 9 to 5.
    Enjoy the family.
    Leave the "flat whatever" rhetoric
    to IT pimps.
    You are a smart man, you can do it.

  2. Ram,

    Started enjoying the Time change from today. It was so comfy to sleep for another one hour in the bed this morning especially when it was cold outside. We need to think about the time when we call India.

  3. Enjoyed the extra one up early to watch India being beaten by Australia.!

    Its good to get up when it is not so dark..but it gets dark at 5.00 here.!


    Flat world - I went for a Seminar on Saturday organized by in Santa Clara. Came back with a lot of energy.! What a flat it is today.!! Unbelievable.

  4. Since 1966, most of the United States has observed Daylight Saving Time from at 2:00 a.m. on the first Sunday of April to 2:00 a.m. on the last Sunday of October. Beginning in 2007, most of the U.S. will begin Daylight Saving Time at 2:00 a.m. on the second Sunday in March and revert to standard time on the first Sunday in November. In the U.S., each time zone switches at a different time.

    In the European Union, Summer Time begins and ends at 1:00 a.m. Universal Time (Greenwich Mean Time). It begins the last Sunday in March and ends the last Sunday in October. In the EU, all time zones change at the same moment.

    Rationale and original idea
    The main purpose of Daylight Saving Time (called "Summer Time" in many places in the world) is to make better use of daylight. We change our clocks during the summer months to move an hour of daylight from the morning to the evening. Countries have different change dates. Glide your cursor over the map to see how changing the clocks affects different latitudes.

    If you live near the equator, day and night are nearly the same length (12 hours). But elsewhere on Earth, there is much more daylight in the summer than in the winter. The closer you live to the North or South Pole, the longer the period of daylight in the summer. Thus, Daylight Saving Time (Summer Time) is usually not helpful in the tropics, and countries near the equator generally do not change their clocks.

    A poll conducted by the U.S. Department of Transportation indicated that Americans liked Daylight Saving Time because "there is more light in the evenings / can do more in the evenings." A 1976 survey of 2.7 million citizens in New South Wales, Australia, found 68% liked daylight saving. Indeed, some say that the primary reason that Daylight Saving Time is a part of many societies is simply because people like to enjoy long summer evenings, and that reasons such as energy conservation are merely rationalizations.

    However, Daylight Saving Time does save energy. Studies done by the U.S. Department of Transportation show that Daylight Saving Time trims the entire country's electricity usage by a small but significant amount, about one percent each day, because less electricity is used for lighting and appliances. Similarly, in New Zealand, power companies have found that power usage decreases 3.5 percent when daylight saving starts. In the first week, peak evening consumption commonly drops around five percent.
    Energy use and the demand for electricity for lighting homes is directly related to the times when people go to bed at night and rise in the morning. In the average home, 25 percent of electricity is used for lighting and small appliances, such as TVs, VCRs, and stereos. A good percentage of energy consumed by lighting and appliances occurs in the evening when families are home. By moving the clock ahead one hour, the amount of electricity consumed each day decreases.

    In the summer, people who rise before the sun rises use more energy in the morning than if DST was not in effect. However, although 70 percent of Americans rise before 7:00 a.m., this waste of energy from having less sunlight in the morning is more than offset by the savings of energy that results from more sunlight in the evening.

    In the winter, the afternoon Daylight Saving Time advantage is offset for many people and businesses by the morning's need for more lighting. In spring and fall, the advantage is generally less than one hour. So, Daylight Saving Time saves energy for lighting in all seasons of the year, but it saves least during the four darkest months of winter (November, December, January, and February), when the afternoon advantage is offset by the need for lighting because of late sunrise.

    In addition, less electricity is used because people are home fewer hours during the "longer" days of spring and summer. Most people plan outdoor activities in the extra daylight hours. When people are not at home, they don't turn on the appliances and lights.

    There is a public health benefit to Daylight Saving Time, as it decreases traffic accidents. Several studies in the U.S. and Great Britain have found that the DST daylight shift reduces net traffic accidents and fatalities by close to one percent. An increase in accidents in the dark mornings is more than offset by the evening decrease in accidents.

    Good topic and I got a platform to share my thoughts.

  5. >>When do you take your International Calls? Which time zone do you guys go by?

    6.30PM to 7PM.

    and its weird if u sit jobless all day long but u have this stupid call to attend. u can't go home early even when u r free...

  6. Anonymous
    Thanks for the suggestion..

    Balaji & Rajan
    I used to enjoy it too.. when I was in US.. as it didn't really impact me.. but now, the extra hour at work.. is a sore pt..
    Most of our work seems to revolved around US EST.. It is a flat world.. but EST centric..

    Thanks for the extensive explanation..

    I do take calls from home and stuff. but would rather spend time with the family...