On Tue, 21 May 2019, Lasher, Beth wrote:
In the year 3001, Daylight Savings time is applied on Sunday March 9, 3001 as expected. (Eastern Standard time). BUT on the following Thursday, March 12, 3001 at 3 am, it seems that another Daylight Savings Time change is applied. After March 12, 3001, the UTC time zone offset for Eastern Daylight Savings Time is 3 hours (not 4) and remains that way until the year 9999. Is this correct? What is the cause of this second time offset change?
Hmmm. On my system, in the year 3001, March 8th is a Sunday, not March 9th! And with zdump I see no extra DST changes for either America/Los_Angeles or EST5EDT: # zdump -vc 2999,3002 EST5EDT EST5EDT -9223372036854775808 = NULL EST5EDT -9223372036854689408 = NULL EST5EDT Sun Mar 10 06:59:59 2999 UT = Sun Mar 10 01:59:59 2999 EST isdst=0 gmtoff=-18000 EST5EDT Sun Mar 10 07:00:00 2999 UT = Sun Mar 10 03:00:00 2999 EDT isdst=1 gmtoff=-14400 EST5EDT Sun Nov 3 05:59:59 2999 UT = Sun Nov 3 01:59:59 2999 EDT isdst=1 gmtoff=-14400 EST5EDT Sun Nov 3 06:00:00 2999 UT = Sun Nov 3 01:00:00 2999 EST isdst=0 gmtoff=-18000 EST5EDT Sun Mar 9 06:59:59 3000 UT = Sun Mar 9 01:59:59 3000 EST isdst=0 gmtoff=-18000 EST5EDT Sun Mar 9 07:00:00 3000 UT = Sun Mar 9 03:00:00 3000 EDT isdst=1 gmtoff=-14400 EST5EDT Sun Nov 2 05:59:59 3000 UT = Sun Nov 2 01:59:59 3000 EDT isdst=1 gmtoff=-14400 EST5EDT Sun Nov 2 06:00:00 3000 UT = Sun Nov 2 01:00:00 3000 EST isdst=0 gmtoff=-18000 EST5EDT Sun Mar 8 06:59:59 3001 UT = Sun Mar 8 01:59:59 3001 EST isdst=0 gmtoff=-18000 EST5EDT Sun Mar 8 07:00:00 3001 UT = Sun Mar 8 03:00:00 3001 EDT isdst=1 gmtoff=-14400 EST5EDT Sun Nov 1 05:59:59 3001 UT = Sun Nov 1 01:59:59 3001 EDT isdst=1 gmtoff=-14400 EST5EDT Sun Nov 1 06:00:00 3001 UT = Sun Nov 1 01:00:00 3001 EST isdst=0 gmtoff=-18000 EST5EDT 9223372036854689407 = NULL EST5EDT 9223372036854775807 = NULL +--------------------+--------------------------+-----------------------+ | Paul Goyette | PGP Key fingerprint: | E-mail addresses: | | (Retired) | FA29 0E3B 35AF E8AE 6651 | paul@whooppee.com | | Software Developer | 0786 F758 55DE 53BA 7731 | pgoyette@netbsd.org | +--------------------+--------------------------+-----------------------+