Timestamps

Particularly when you want to use some of the synchronization features, first make sure that WinSCP will be able to convert timestamps from local conventions to remote server conventions and vice versa.

Conversion

There are several factors that affect conversion and interpretation of the timestamps:

Factor Symptom
Daylight saving time (DST) Timestamps of some files are shifted by one hour.
Server timezone offset Timestamps of all files are shifted by the same time span. Only SCP protocol is affected.
Local file system is FAT File timestamp is always rounded to the next even second. This is property of old FAT filesystem. For the reason WinSCP ignores less than 2-seconds time difference with all its synchronization features. Note that FAT is used rarely nowadays, mostly with removable medias only.
Timestamp precision Files changed shortly after previous synchronization are not synchronized. Only SCP protocol is affected.

Also note that for WinSCP to try to convert file timestamp at all, you need to have transfer option Preserve timestamp enabled.

Windows vs. Unix

For certain reasons NT-class versions of Microsoft Windows (NT, 2000, XP, 2003, 7) shifts timestamps of ALL files by one hour once Daylight Saving Time starts and/or finishes (see note 1). For example, for file created on 2005-02-25 14:00, the Windows applications (like Windows Explorer or WinSCP) will show modification time 2005-02-25 15:00, when DST is in effect. Unfortunately, to allow synchronization functions to work, WinSCP has to apply the same correction to timestamps of remote files as Windows apply to timestamps of local files. As the remote operating system, being typically Unix-style, usually does not perform the Windows NT-style correction, you will see different timestamps in directory listing of WinSCP, than you see in directory listing on the server (for example in ls listing).

Synchronization

If you happen to have the same files locally and remotely with the different timestamps, you can update them without transferring the files again. Use function Synchronize with option Synchronize timestamps only, not files.

Notes:

1) See article Beating the Daylight Savings Time bug