Interesting: If I deny System Services location access for 'Setting Time Zone', my iMac 5K changes the color temperature … (Security & Privacy / Location Services / System Services / Details / Setting Time Zone)
It's due to Night Shift, set it to a custom schedule (or enable location services but only for time zone settings)
(I don't really mind location services with regard to Apple, however, for an iMac, location services are pretty useless.)