USA Daylight Savings Time (DST) - Auto change DST value

Setup, Configuration and Use Scripts & Rules
1

Have a rule that looks at a date/time coming from a Amazon JSON string. It uses the alarm value from it and then calculates the difference in minutes before it goes off to control a HUE light.

In OH 3, this DST value changed based on Spring forward an hour and Fall back an hour. This wasn’t the case with OH 2.

var setAlarmTime = ZonedDateTime.parse(alarmdate + "T" + alarmtime + "000-05:00[America/Chicago]")				// have to change to 06:00 in fall

Is there a way to detect when DST happens within OH and then set the variable offset from -05:00 to -06:00 and visa versa?

Best, Jay

2

I doubt that OH2 itself was the reason at least I haven’t realized it.
As far as understand DST is done on OS level.

Linux command to get the date when the changes happen is e.g.:

zdump -v America/Chicago  -c $(date '+%Y'),$(date -d '+1 year' '+%Y') | awk -v y=$(date '+%Y') '$6==y && $15~1 {print $4, $3, $6}'

which will result in

13 Mar 2022
6 Nov 2022

you need to play around with the awk arguments to e.g. add the hour/minute/second when the change exactly will take place.

Without piping zdumps output into awk the output looks like:

America/Chicago  -9223372036854775808 = NULL
America/Chicago  -9223372036854689408 = NULL
America/Chicago  Sun Mar 13 07:59:59 2022 UT = Sun Mar 13 01:59:59 2022 CST isdst=0 gmtoff=-21600
America/Chicago  Sun Mar 13 08:00:00 2022 UT = Sun Mar 13 03:00:00 2022 CDT isdst=1 gmtoff=-18000
America/Chicago  Sun Nov  6 06:59:59 2022 UT = Sun Nov  6 01:59:59 2022 CDT isdst=1 gmtoff=-18000
America/Chicago  Sun Nov  6 07:00:00 2022 UT = Sun Nov  6 01:00:00 2022 CST isdst=0 gmtoff=-21600
America/Chicago  9223372036854689407 = NULL
America/Chicago  9223372036854775807 = NULL