How to make groff use local timezone?

[Jim Avera]

The registers \n[mo] \n[dy] etc. seem to not respect the current time 
zone, and so (for example) the \*(DT string provided by -mm shows the 
wrong day for several hours each day.

I suspect groff is always in UTC (but haven't confirmed).   Is this a 
bug or intended?

How can I make mm's \*(DT show the correct date in my timezone? I know I 
can manually override the automatic value using .ND and some kind of 
wrapper script to auto-insert the macro call or something... but that's 
not very attractive.

Thanks in advance for any suggestions.