# Decomposition of seasonal time series interpretation

I have the below stl() (with s.window="periodic") decomposition plot of a time series which I would like to analyse and model. The time series is hourly with data from Dec 2017 up until 17 Sep 2018. I am not very sure on how to interpret the trend. Does it mean that my data has no overall trend? What does the "wiggly" trend line ,like so, indicate?

Apart from this, I plotted the ACF and the PACF plots for the series (without differencing or transforming) and I have the below plot and I cannot seem to understand what the the ACF plot is telling me.

• stl decomposes your time series into it's components so that you can see which component causes the most variability (the smaller the bar on the right the higher the variability). The ACF and PACF plots are telling you that you have a seasonal trend present in your data Sep 26, 2018 at 11:26