Improving SD card logger script

The problem is that when i add a clock module to my project, it stops logging when the log-file is about 100 kb (although the memory card is 2 Gb).

Does it stop logging, or does it simply take longer to log the data?

Why not create a new file before the old one gets that big? One file per day, or week, or month, or whatever.

Is the temperature really changing that much? Logging once every 5 minutes is probably good enough, isn't it?