Info on timechanges in Sweden

Ivan Nilsson ivan at
Fri Apr 13 22:46:29 UTC 2001

I'd like to make a contribution to the timechanges in Sweden found in your timezone file.

Sweden has never had the Mean Time of Stockholm as national Standard Time, and never switched to/from summertime at 1:00 from 1980 onwards. The correct entries are:

1:12:12                        LMT              1879  (1878 May 31 is incorrect)
1:00:14                        SEST            1900  (change at 01:00 is incorrect)  # Sweden Standard Time
1:00:00                        CET              1916 May 14 23:00    (April 14 is incorrect)
1:00:00        1:00          CEST           1916 I'm not sure about this, see explanation below.

All of the above is stated in lawtexts (unfortunately I have only found them in Swedish).

The law "Svensk författningssamling 1878, no 14" about standard time in 1879:
>From the beginning of 1879 (that is January 1  0:00) the time for all places in the country is "the mean solar time for the meridian at three degrees, or twelve minutes of time, to the west of the meridian of the Observatory of Stockholm". The law is dated 31 May 1878.
The observatory at that time had the meridian 18 degrees 03' 30" eastern longitude =
1 hour 12 minutes 14 seconds in time. Less 12 minutes give the national standard time as
1 hour 00 minutes 14 seconds ahead of GMT. (The observatory is in the centre of Stockholm.)

I suggest SEST rather than SST or ST because other time standards already use them (SE = the internation code for Sweden).

About the beginning of CET in Sweden. The lawtext ("Svensk författningssamling 1899, no 44") states, that "from the beginning of 1900... ... the same as the mean solar time for the meridian at the distance of one hour of time from the meridian of the English observatory at Greenwich, or at 12 minutes 14 seconds to the west from the meridan of the Observatory of Stockholm". The law is dated 16 June 1899. 
In short: At 0:00:00 January 1 1900 the new standard time i Sweden is 1:00:00 ahead of GMT.

I have photo copies of these laws. If you like I can scan them and mail them to you.

Now the summertimes.

1916: The lawtext ("Svensk författningssamling 1916, no 124") states, that "May 15 1916 is considered to begin one hour earlier". It is pretty obviuos that at 23:00 May 14 the clocks are set to 0:00 May 15 (thus the timezone file is correct).

Further the law says, that "September 30 1916 is considered to end one our later". This is a most ambigous statement.
One way to interprete this: At 0:00 October 1 the clocks are set back to 23:00 Sept 30. But in practice it appears that the changes somehow involved 1:00 on October 1.
A news report I recently found is not clear on what exactly happened except that 1:00 October 1 is involved. The text report about trains standing still for one hour in the night and is written in a way that invistes two interpretations:
1. At 0:00 October 1 the trains stop and stand still for one hour, and then the clock is set to 0:00 summertime October 1 and the trains continue the journey.
2. At 1:00 October 1 the trains stop, the clock is set back to 0:00, and when it again is 1:00 summertime the trains move again.
I am sorry I have not been able to get this matter crystal clear. I live close to a university so I hope I will able able to find sometime more useful there.

The rules given in the timezone file for the summertimes from 1980 onwards have the correct dates, but I am afraid the times are incorrect. The laws regulating summertime explicitly states that, when summertime begins, the clocks are set forward from 2:00 to 3:00 in the night. When summertime ends, the clocks are set back from 3:00 to 2:00 in the night. So, the time 1:00:00 is in no way involved in the summertime changes in Sweden nowadays. The laws regulating this are available on the site of the Swedish Parliament beginning with 1985 - the laws regulating 1980 - 1984 is not available on the site (to my knowledge they are only available in Swedish): 
(type "sommartid" without the quotes in the field "Fritext" and then click the Sök-button).

I really appreciate your excellent work compiling all that time information from all around the world. 

/Ivan Nilsson

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