I have just been researching differences in historical temperature between the Atlantic Coast of West Wales and the North Sea coast of Europe (my final project for the plotting and charting module in the Data Science course at Coursera/University of Michigan).
I used Met Office data from the Netherlands and the UK to compare temperature trends in West Wales (where I grew up) and the North Sea coast of Europe (where I now live).
I did this by comparing weather station data from Aberporth (West Wales) and Vlissingen (Netherlands). The full write up showing all the steps I went through to get this is here (with my source code).
The graphic shows the difference trend between summer and winter temperatures at the two locations. There seems to be a long term trend that the winter difference is decreasing, while the summer difference has increased.
(Do take a look at the full write-up here on Github. The way that the trend emerges from the raw data, due to the process of selecting, averaging and plotting, is interesting in itself.)