FileBot

Whoever setup your website screwed up the time zones. When registering and selecting UTC -7, Denver (Mountain Time) is not listed. Instead Denver is listed under UTC -6. This is incorrect, Mountain Time is SEVEN hours behind UTC, NOT 6. You guys should really fix that, it kind of seems unprofessional to me.

According to Google, Greenwich Mean Time is 6 hours ahead of Denver, CO, USA:
https://www.google.com/search?q=what+ti ... red+to+GMT

Presumably, phpBB is using Mountain Daylight Time (MDT) (GMT-6) for Denver. If you are from Denver and say that this TZ is not typically used there, then please report this issue to the phpBB folks.

If you find any bugs in the phpBB software then you can report them here:
https://www.phpbb.com/community/viewforum.php?f=64

I think that might be it actually. This site is not the only forum I have noticed this on. The others must be using phpBB too. I'll check that out.

Since Denver is currently 6 hours ahead, selecting Denver (GMT-6) seems like the correct choice to me.

In Winter, when Denver switches to Winter Time (GMT-7) then the forum software will probably adjust all times and settings accordingly to give you the correct local time for your locale.