I've just run my E&W summer index up to the end of July to see how the summer so far compares historically. The answer is a bit meh.
As a quick recap, I use E&W mean temperature, precipitation and sunshine hours from 1971 to now, normalised so that each time series has an equal long term Std deviation i.e. the influence of variability in each measurement is equal.
June scores a creditable 140 (vs 1971-00 mean of 125), putting it 9th in the list out of 54; July scores only 161, in 11th place. That puts it behind many recent Julys including 2013 and 2014, 1999, 1990 (though interestingly, and contrary to received wisdom, not far off July 1995 and ahead of July 1975).
This is almost entirely down to disappointing sunshine hours. 212.7 in the month, an average of only 6.9 hours per day. Less sunshine than June. Jiries is, as so often, right on the money.
The more interesting stats are for the last 12 months. Last Autumn was 9th highest, winter 3rd, spring 6th, and summer looks likely to be in the top 5 or 6 at least. The highest scoring calendar year by some way is 2003 with a score of 90, followed by 1989 then 2018. Record could be up for grabs this year through consistently good scores rather than any standout months.
Brockley, South East London 30m asl