Hi, and welcome to the forum. We probably need to see your actual code and some sample data. You may want to have a look at FAQ: How to do a minimal reproducible example ( reprex ) for beginners
A handy way to supply some sample data is the dput() function. In the case of a large dataset something like dput(head(mydata, 100)) should supply the data we need.
BTW you mean timeVariation do you not?
Ah, wait a minute. I just tried this on a package dataset and it gives the same results as you are getting. The plots appear to start at time zero so from 0:23 gives you 24 hourly data points.