Why is the date in dmesg wrong?
Solution 1:
ridgy posted a comment explaining this, and the original poster has verified that the explanation is correct:
The manpage (man dmesg) says:
Be aware that the timestamp could be inaccurate! The time source used for the logs is not updated after system SUSPEND/RESUME.
Maybe your system was suspended before?
Solution 2:
Workaround is journalctl with -k, --dmesg. I am using -k as it is shorter:
journalctl -k
It will show only kernel messages and correct time.
To show only kernel lines matching phrase:
journalctl -kg phrase