Proposal for a finer adjustment of summer time (daylight saving time)
When you live 56 degrees of latitude away from the equator, the observance of summer time (daylight saving time) is really wonderful. It gives you longer evenings with daylight in the summer, and its absence in the winter makes it easier to get up in the morning.
Still, one must admit it seems a bit arbitrary to adjust the clocks by plus 1 hour once in the spring, and then by minus 1 hour in the autumn. Why don't we make the transition more smooth, and the adjustment more continuous?
A simple example
Consider a person living in Copenhagen (55.7 degrees North). Every workday he has to get up at, say, 6 a.m. Now, getting up before sunrise is neither comfotable nor healthy. On the other hand, getting up after sunrise means some hours of light get "wasted". Wouldn't it be ideal to adjust the clocks to ensure that sunrise was always at 6 a.m.?
Every weekend, on the night between Saturday and Sunday, simply adjust the time so the sunrise will still be at 6 a.m.
For Copenhagen, we get the following table:
|Improved summer time (daylight saving time) rule|
|On the night between Saturday and Sunday||advance clocks by||Time zone is then|
|02 January 2011,||+2 minutes.||UTC-01:37.|
|09 January 2011,||+4 minutes.||UTC-01:33.|
|16 January 2011,||+8 minutes.||UTC-01:25.|
|23 January 2011,||+11 minutes.||UTC-01:14.|
|30 January 2011,||+12 minutes.||UTC-01:02.|
|06 February 2011,||+14 minutes.||UTC-00:48.|
|13 February 2011,||+15 minutes.||UTC-00:33.|
|20 February 2011,||+17 minutes.||UTC-00:16.|
|27 February 2011,||+17 minutes.||UTC+00:01.|
|06 March 2011,||+17 minutes.||UTC+00:18.|
|13 March 2011,||+18 minutes.||UTC+00:36.|
|20 March 2011,||+19 minutes.||UTC+00:55.|
|27 March 2011,||+18 minutes.||UTC+01:13.|
|03 April 2011,||+18 minutes.||UTC+01:31.|
|10 April 2011,||+18 minutes.||UTC+01:49.|
|17 April 2011,||+17 minutes.||UTC+02:06.|
|24 April 2011,||+17 minutes.||UTC+02:23.|
|01 May 2011,||+15 minutes.||UTC+02:38.|
|08 May 2011,||+15 minutes.||UTC+02:53.|
|15 May 2011,||+13 minutes.||UTC+03:06.|
|22 May 2011,||+11 minutes.||UTC+03:17.|
|29 May 2011,||+9 minutes.||UTC+03:26.|
|05 June 2011,||+6 minutes.||UTC+03:32.|
|12 June 2011,||+3 minutes.||UTC+03:35.|
|19 June 2011,||0 minutes.||UTC+03:35.|
|26 June 2011,||-4 minutes.||UTC+03:31.|
|03 July 2011,||-6 minutes.||UTC+03:25.|
|10 July 2011,||-8 minutes.||UTC+03:17.|
|17 July 2011,||-11 minutes.||UTC+03:06.|
|24 July 2011,||-11 minutes.||UTC+02:55.|
|31 July 2011,||-13 minutes.||UTC+02:42.|
|07 August 2011,||-13 minutes.||UTC+02:29.|
|14 August 2011,||-14 minutes.||UTC+02:15.|
|21 August 2011,||-13 minutes.||UTC+02:02.|
|28 August 2011,||-14 minutes.||UTC+01:48.|
|04 September 2011,||-13 minutes.||UTC+01:35.|
|11 September 2011,||-14 minutes.||UTC+01:21.|
|18 September 2011,||-13 minutes.||UTC+01:08.|
|25 September 2011,||-14 minutes.||UTC+00:54.|
|02 October 2011,||-13 minutes.||UTC+00:41.|
|09 October 2011,||-14 minutes.||UTC+00:27.|
|16 October 2011,||-15 minutes.||UTC+00:12.|
|23 October 2011,||-14 minutes.||UTC-00:02.|
|30 October 2011,||-15 minutes.||UTC-00:17.|
|06 November 2011,||-14 minutes.||UTC-00:31.|
|13 November 2011,||-15 minutes.||UTC-00:46.|
|20 November 2011,||-14 minutes.||UTC-01:00.|
|27 November 2011,||-12 minutes.||UTC-01:12.|
|04 December 2011,||-11 minutes.||UTC-01:23.|
|11 December 2011,||-8 minutes.||UTC-01:31.|
|18 December 2011,||-6 minutes.||UTC-01:37.|
|25 December 2011,||-2 minutes.||UTC-01:39.|
|01 January 2012,||+1 minute.||UTC-01:38.|
Note: Copenhagen, under the current system, uses UTC+01:00 in winter and UTC+02:00 in summer.
- People get up at sunrise every morning. This is natural; almost all diurnal animals in the wild practice this.
- No great jumps or "discontinuities" in clock time. Only small weekly adjustments.
- Saves some energy for the benefit of global climate (although not much since most energy consumption in a modern society is unrelated to lighting).
- More happiness to the people: Bright summer nights, no dark winter mornings.
- Table above depends strongly on latitude. Having different time systems for each latitude gives greater complexity than the current system where time zone depends (mostly) only on longitude.
Questions and answers
- I get up at 8 a.m., not 6 a.m. What would be ideal for me?
- Each date, you adjust by the same number of minutes. Only, your time zone will always be 2 hours east of what is indicated in the table. (Actually, the time zones in the above table are pretty much appropriate for morning persons. People with a more evening-active circadian type ("B persons" or "owls") would certainly prefer more easterly time zones.)
- Why is it for 2011? I need a table for another year.
- Thanks to the leap years in the Gregorian calendar, the seasons are fixed with respect to the dates, so each year looks more or less the same. (And thanks to leap seconds, night and day stay fixed with respect to UTC time in the long term.) Sundays will fall on different dates, of course.
- I live in a different latitude? Where's my table?
- That's the problem. You can calculate your own table by going to Sun Rise Table for One Year at USNO. Gives you sunrises in a fixed time zone (without summer time (daylight saving time)). Look at all Wednesdays (they are midway between Sundays). Calculated for each Wednesday the difference needed to make the sun rise at 6 a.m. exactly.
- Why not change clocks every night, then sunrise will be exactly 6 a.m. every day (not just Wednesdays)?
- You could do that as well.
- Do you really think people will implement your system?
- No. This is just to illustrate what an ideal summer time (daylight saving time) might look like. It might help some people understand why it is a good idea to have clocks jump forward in the spring and back again in the autumn. Some opponents of summer time (daylight saving time) seem to fail to realise how adjusting the clocks can bring more happiness to all of us in the summer, and in the winter.