In message , Gavin Staples
writes

I did not realise that this had ever been recorded. What
dreadful summers those must have been. 13.6C for an August CET. These days
we take for granted an August CET of at least 16C or more. Perhaps we
shouldn't :-)

These summer's came at the end of the period know as the "little Ice
Age", so cold summers were the norm then and for a few hundred years
prior to that in what is known as a 'stadial'.

Recent warmth is a a cyclical shift that is quite normal in any
interglacial back to relative warmth.

Well that's what I teach my students anyway!
--
Steve Jackson