Question

What’s the correct time zone offset for “Januray, 1st 1000” for a Java program running in Zurich?

Background: When I use joda-time 2.1,

new DateTime( 1000, 1, 1, 0, 0, 0, 0, DateTimeZone.forID( "Europe/Zurich" ) ).toString()

gives me

1000-01-01T00:00:00.000+00:34:08

which seems odd because of the time zone offset 00:34:08 (an 34:08 minute offset??). Looking into the europe entry in the IANA Timezone Database, I see this:

# Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
Zone    Europe/Zurich   0:34:08 -       LMT     1848 Sep 12
                        0:29:44 -       BMT     1894 Jun # Bern Mean Time
                        1:00    Swiss   CE%sT   1981
                        1:00    EU      CE%sT

This gives all times before Sept. 12th, 1848 an offset of 34:08 which doesn’t seem right.

Can someone shed some light on this?

Answer 1

Wikipedia, on European time zones:

1894

• Switzerland switches from UTC+00:30 to CET
• Liechtenstein introduces CET.
• Denmark adopts CET.

I suspect the leftover seconds are compensatory changes that have been made since 1894, leap seconds and the like.