This chart is of 365 day centred rolling daily mean CET temperature anomalies for the last 30 years. Just to complicate things, I’ve overlaid a 14 day moving average on top of this just to smooth things out a bit. The LTA that I have used to calculate the anomalies is the latest possible 30 year period that I could use i.e. 1987-2016. The decadal linear trend for the last 30 years is just +0.08°C per decade. Of course, things would look different if I had used a longer period or an earlier LTA, but such is the way with statistics.