debian time

check whether your system uses utc or localtime
$ cat /etc/adjtime

if utc, all is well. you might find hwclock set to localtime.

it is recommended to use utc for every os. the only objection might be from windows users. you can set a registry key for windows to use utc. this is far more preferable than tinkering with the hardware clock, as your system will never be able to catchup with drift.

# hwclock --adjust --utc
or
# hwclock --systohc --utc

check your timezone
$ cat /etc/timezone

if not correct
# dpkg-reconfigure tzdata

ntp sync your clock and adjust hwclock again, if need be.
rdate -nuv uk.pool.ntp.org