DST daylight saving time

3277061 – ABAP Date/Time Conversion with DST for SELECT_MESSAGES

DST (daylight saving time) starts in the spring (= a loss of one hour) and ends in the fall (= a gain of one hour ). For clock adjustment, one must remember “Spring forward, Fall back”.

Spring forward:

Fall backward:

Method 1: shut down the system

During the switch, simply shutdown the SAP system, for the entire duration of the double hour, and bring it up only after the double hour has passed. Thus, the SAP Kernel software does not have to deal with any possible mismatch of standard time and local time. The big setback off course is that you have work shutting down and starting up the systems in the middle of the night. And the business cannot work during this time. Long running weekend jobs might be interrupted as well and need to be redone.

Method 2: zero downtime by slowing down the time

Slow down the time by half, during the double hour, so that the 2 hour period is treated as one hour.

In SAP, executing this is easier than it appears by setting the parameter zdate/DSTswitch_contloctime = on which is default in the latest kernel release 6.40 and higher, so that you can make your SAP system see a continuous time with a deviation of 30 minutes.

During the conversion from summer time to winter time, there is a “doubled” hour.  In Europe, for example, the summer time is reset to winter time on the last Sunday in October between 2 a.m. and 3 a.m.

1:00    1:30    2:00    2:30    2:00    2:30    3:00 official time


How to check the time zone at different levels

  • Run the report from SA38: TZCUSTHELP (trouble shooting time zone)
  • Run the report from SA38: RSDBTIME (time diagnosis)
  • Run this function module in SE37: TZ_SYSTEM_GET_TZONE
  • Run this report fromSA38: TZONECHECK 

DST in non-ABAP systems

For DST in non-ABAP systems check these notes:


Excellent blog from SAP: Daylight Saving Time and Slowing Down The Time.

Reference OSS notes:

ABAP programming DST specific notes: