Google does "leap smearing" which seems like the best human solution to this problem: https://googleblog.blogspot.com/2011/09/time-technology-and-...

standardizing leap smearing algos and constants could work

-Bottom layer is atomic clock seconds -We define targeted relationship between current UTC and atomic counter that will occur on a given day and time X -Time is interpolated to drift UTC into place by the given day and time X -Standards body can adjust time on some regular basis by its relationship to the atomic clock and publish the algo to convert from atomic to UTC