Different timestamp when copying files between Windows and Linux

I'm using mount.cifs to map a windows folder, then I copy hundred of files at once from windows to Ubuntu. After that all files are syncronized and the modification times as well. On Windows using explorer I see that not all but a very few files have a difference of 1 hour from the copied files on Ubuntu. Why on windows almost all files match the modification time but some do not? I had to edit this post to explain that I think it is not related to the UTC and it is not a duplicated question. I'm just comparing a list of over 2000 files with the filenames and timestamps, one file generated on Windows and one file generated on Linux. I compare these 2 files and then I copy only the modified files. Even these files were all updated I keep copying 14 files every time.