[tz] [english 100%] historic Oslo times

[Meno Hochschild]

Alternatively, just a new ZONE line could be inserted for the period in 
question (1940-08-10 23:00 and 1942-11-02 03:00) with fixed DST offset 
+01:00 in the RULES-column and same GMTOFF-column and FORMAT-column with 
content CEST. Previous line would point to Norway-rule, next line to 
C-Eur-rule.

Am 05.03.2015 um 00:57 schrieb Meno Hochschild:
> Recently I noticed following strange detail of Europe/Oslo during the 
> years 1940-1942:
>
> The site http://www.timeanddate.com/time/zone/norway/oslo reports for 
> these years that Oslo kept summer time between 1940-08-10 23:00 and 
> 1942-11-02 03:00. But I cannot find a way in tz-data how to construct 
> it. Maybe I have overlooked something.
>
> Rule Norway 1916 only - May 22 1:00 1:00 S
> Rule Norway 1916 only - Sep 30 0:00 0 -
> Rule Norway 1945 only - Apr 2 2:00s 1:00 S
> Rule Norway 1945 only - Oct 1 2:00s 0 -
> Rule Norway 1959 1964 - Mar Sun>=15 2:00s 1:00 S
> Rule Norway 1959 1965 - Sep Sun>=15 2:00s 0 -
> Rule Norway 1965 only - Apr 25 2:00s 1:00 S
>
> # Zone NAME GMTOFF RULES FORMAT [UNTIL]
> Zone    Europe/Oslo    0:43:00    -    LMT    1895 Jan 1
> 1:00 Norway CE%sT 1940 Aug 10 23:00
> 1:00 C-Eur CE%sT 1945 Apr 2 2:00
> 1:00 Norway CE%sT 1980
> 1:00 EU CE%sT
>
> The Norway-rules do not catch the year 1940, so cannot indicate any 
> summer time until 1940-08-10. Then the C-Eur-rule takes effect but see 
> here:
>
> Rule C-Eur 1940 only - Apr 1 2:00s 1:00 S
> Rule C-Eur 1942 only - Nov 2 2:00s 0 -
>
> The rule for 1940 cannot be applied because 1st of Apr is clearly 
> before the UNTIL-date of zone line in question when changing from 
> Norway-rule to C-Eur-rule. I assume we are missing an extra 
> Norway-rule for 1940 only changing to summer time on 1940-08-10 and 
> have then to shift the UNTIL-date in second ZONE line a little bit 
> (for example to 1941).
>
> Thanks in advance for any help
>
> Meno Hochschild
>
>