Neither UTC nor local times are times in the physical sense. At most you can say that they are times passed from a non-constant origin of time, which changes frequently and in an unpredictable mode for the future.
People always forget what UTC and local times really are and they very frequently make mistakes in their handling, especially for future events.
The foolproof way, as advocated by Bernstein and others, is to use only TAI for internal timekeeping and computation, and to convert to UTC or local times only the values that will be seen by human eyes.
I have done like this since many years ago, and it was always simpler for me. It would have been much simpler if this would have been a general practice, as that would have eliminated the useless conversions required for communication with other systems that use UTC, e.g. when using NTP.
