According to wikipedia, last year was the hottest year in this dataset with an average temperature of 10.94 °C.
Looking at the black line that represents last years temperatures it was the winter and autumn that were far above average. Instead of a scorching hot summer the three record hot days were in October and December. No day in 2014 was the coldest for that date in the recorded time.
The wikipedia page on this dataset shows the average temperature of this dataset rising over time