This past Sunday morning Daylight Saving Time ended at 2:00AM and the clocks rolled back an hour, giving us all some extra rest. However, for data process historians and engineers like yourself, this semi-annual phenomenon can be anything but relaxing! In fact as you have learned, the Daylight Saving Time (DST) scenario is one of the most difficult situations for a data historian to handle. Let me explain for others, not as familiar, while I answer your question.
Imagine you were to search for data at 1:35AM on the Sunday of DST. How would the computer know if you meant the first 1:35AM or the second 1:35AM of the morning? The Canary Historian solves this problem by storing all the data with UTC time stamps. UTC stands for Coordinated Universal Time and is the basis for civil time today. Note, this is a time standard, not a time zone.
I smile knowing our clients never have a firestorm of issues related to DST transitions; I hope that helps them sleep as peacefully as I do.