ConvertTimeZone( has limitations

Before anyone might get bit (as I already have), the ConvertTimeZone( function is limited in accuracy as it relies on Apple’s ‘clever code’ to adjust for the time difference between 2 locations taking into consideration that daylight savings time occurs on different dates in different locations.

But alas, Apple’s code does not take into consideration that daylight savings time occurs not at midnight, but at different times of the day (based on the location’s custom).

ie. Daylight Savings Time occurs in New York on March 14, 2021 @ 2:00 am. But as the ConvertTimeZone( function uses Apple’s code, the difference in time between New York & Sydney will be identical on March 14, 2021 whether the time is 1:01 am or 2:01 am.

I had to write my own code to adjust for the different time of day that each location’s daylight savings time kicks in. Most won’t have to but be forwarned if it is critical to your application.

The result of these limitatons can result in incorrect day of week or date calculations as well. Be forewarned. Zone math is not simple.