The three month period May to July 2018 was truely exceptional for NW England and North Wales, the closest I can think of coming to it in my life time would be May to July 1989 and even then it wasn't that close. 

I did a "summer" index for that period and it came in at around 296 which is better than every summer measured by the index since 1900 except 1995 and 1976

Summer 1976: 301

Summer 1995: 298

May to July 2018: 296

The one thing that stands out more than anything for me from that period were the sunshine levels, they were phenomenal! Looking at the Met Office regional figures for the NW England and North Wales area

May 2018: 256.5hrs  sunniest May ever

June 2018: 257.1hrs 4th sunniest June ever

July 2018: 250.1hrs: 4th sunniest July ever

Total of 763.7hrs  or 8.3 hrs of sunshine per day 

Sunniest ever season for the area is summer 1976 with a total of 681.5hrs or 7.41hrs of sunshine per day.

May to July 2018 recorded 82.2hrs more sunshine than during summer 1976.

Sunshine totals for May-July 2018

Ronaldsway: 754hrs

Shap Fell: 689.2hrs

RAF Valley: 779.9.hrs

Aberardon: 801.9hrs

Maximum temperatures are another standout for that period.

May 2018: 17.3C  2nd warmest ever May

June 2018: 20.3C 2nd warmest ever June

July 2018: 22.3C 3rd warmest ever July

The maximum temperature for May to July 2018 average at just under 20.0C. They were only 5 summers since 1929 warmer than this in terms of maximum temperatures. 

Rainfall totals are interesting, only summers 1976 and 1995 were drier than May to July 2018 for summers since 1929. 

May to July 2018 will linger long in the memory: hours of sunshines, land getting parched and cracked, the smoke coming off the Pennines and Winter Hill, the glorious sunsets almost every day. It will take something for a future May to July period to surpass it. 

Yep. Was a stunning spell of weather, by far one of the best I've experienced. Felt like a proper southern European summer!

Sad to see it go, but all things have to end I suppose.

None of the above stats surprise me at all and I absolutely agree it’s been as good as the best summers I’ve ever experienced, which include 1959, 1976 and 1989.  Superb!  More like these please God!  

What stands out for me is the humidity stayed reasonably low throughout May and June and the temperatures were never extreme. Made it all the more useable.

Some very impressive stats there.

"May to July 2018 recorded 82.2hrs more sunshine than during summer 1976."

It needs to be borne in mind that the maximum possible hours of sunshine in May are greater than in August, as it's closer to the solstice. But even if you allow for that, I expect that 2018 would have "won".

It truly was a magnificent summer the best since `76. The period from the Friday before the 1st bank holiday in May until August the 10th was outstanding for sunshine and high temperatures as well as almost zero rainfall. Id give summer 2018 9/10 based on the benchmark of 10/10 for 1976.