Hello. 

I am a clinical biochemist and not well versed in handling the TZ database. I am investigating a software problem related to hospital patient data management that appears to be triggered when the software encounters a patient record with a date-of-birth that coincides with a historic daylight saving time Spring transition date.  Through this investigation I have learned many details about the history of daylight saving time, but I often question the reliability of sources of information.  It appears that many use the tz database as a source of truth. 

I am seeking assistance to query the tz database to determine the entries in the database for Area /Location    America/Regina to determine the (1) daylight saving time Spring transition date and  (2) daylight saving time Spring transition hour from 1900 to 1966. 

I understand there were 10 years between 1930 and 1941 when the hour of Spring daylight saving transition was 0000 (midnight)  to 0100.  I would like to confirm these entries are in the tz database.   I have numerous references that daylight saving time was also observed in America/Regina  during world war ONE ( 1914-1918) and I am uncertain if those entries are in the tz database or the hour of those transitions. 

I am uncertain if it is appropriate to ask for this type of assistance on this discussion group. 

Thank-you very much, regards, Andrew

Dr. A.W. Lyon

Dept Pathology and Laboratory Medicine

University of Saskatchewan