Is this a dual boot with windows?
If so it might be because windows is set to local time and bt is using UTC.
Or your bios uses something different than what the OS is set to.
Check the bios,Then go from there.
Try setting it manually
You can keep bt from using UTC by editingCode:hwclock --set --date="YYYY-MM-DD HH:MM:SS TIMEZONE" hwclock -s
finding the line that has UTC=yes and change it to no