Correlating Log files are an important aspect when responding to incidents/attacks/outages regarding your Cisco devices.
However I have noticed for a while that my logging timestamps are off an hour from the actual clock synced by NTP.
After some digging I realized that Cisco devices use
service timestamps log datetime
as a default. You can check the default values using the command:
sh run all | inc timestamp
In order for your logs to use the local clock time you need to issue the command
device(config)# service timestamp log datetime localtime
From now on, your logging timestamp should be identical to your local time on the device.