Chhers Steve - Thanks. I only did the calculation at random.
I'll now do it thoroughly. 
The CETs for the summer of 1976 were as follows. These figures are from the Hadley Table.
June 17.0C July 18.7 August 17.6. Add those 3 together and it comes to 53.3. So we need to get to that at least.
So far this summer we have.
June 16.1 July 19.1. . Those added together come to 35.2.
So therefore that makes it 53.3 - 35.2 - which equals 18.1C
So we need to better 18.1C as you pointed out above. That is quite a hard ask for August. It was the June that made it for 1976. Take 1995 for example - June was rubbish - but July and august of 1995 were incredible.
We had a pretty good June this year - but the cool nights in it made it come in 0.9C below 1976.
Originally Posted by: Hungry Tiger