How to check if hardware clock is in UTC or Local time

Ubuntu 15.04 and later uses systemd as the default init system and includes the timedatectl program. Running timedatectl will output:

      Local time: Tue 2016-02-02 09:47:54 MST
  Universal time: Tue 2016-02-02 16:47:54 UTC
        RTC time: Tue 2016-02-02 16:47:54
       Time zone: America/Denver (MST, -0700)
 Network time on: yes
NTP synchronized: no
 RTC in local TZ: no

RTC time is the hardware clock. Compare it to the Local time and Universal times returned by timedatectl to determine how the hardware clock is set.

RTC in local TZ: no means the hardware clock is interpreted as UTC

RTC in local TZ: yes means the hardware clock is interpreted as local time

To switch using timedatectl

sudo timedatectl set-local-rtc 0 sets RTC to UTC

sudo timedatectl set-local-rtc 1 sets RTC to local time

Switch using config file

Setting the UTC= setting in /etc/default/rcS will change how the system interprets the hardware clock (UTC=yes or UTC=no).

sudo hwclock --debug

Gives you the unmodified time before spitting out the interpreted (local or UTC) answer.