How can an entire country be better than average? Is that the thermal anomaly? Global warming?
I'm not sure what you're saying.
The map I posted shows the percentage of sunshine over 2018, compared to previous years, averaged over 1981 to 2010.
The sunshine anomaly last year was due to a prolonged anticyclonic period from April to August. It's not a thermal anomaly because clear skies also increase thermal losses, causing the temperature to drop at night, especially in winter, when more sunshine will often give lower temperatures, both day and night.
Temperature-wise, 2018 was another warm year, the 7th on record, across the UK, going back to 1910 and the 4th warmest for central England going back to 1659, despite a cold spell from February to March.
https://www.metoffice.gov.uk/climate/uk/summaries/2018/annualhttps://www.metoffice.gov.uk/hadobs/hadcet/ssn_HadCET_mean.txtWeather or climate change? No one knows for sure. In the UK, with the exception of 2018 and 2013, summers since 2007 have become wetter and less sunny, than those in the late 1980s to early 2000s. No one knows why. Some say it's climate change and have linked it to increase ice melt over Greenland, others say it's part of a natural cycle. I tend to side with the latter and think increased ice melt over Greenland is more likely to be an effect of the weather pattern which brings increased summer rainfall to the UK, rather than a cause.