I was walking around over in London one trip over there. Heck, it was about 70 and felt cool so I put on my summer coat. I ended up packing that coat over my shoulders for the entire walk.
When I was there over the summer of '89, the locals told me they hadn't seen it that hot in a dog's age. It was really brutal, and at that time, most buildings in England didn't have air conditioning.
I quickly discovered that if you wanted to take in a movie, it was best to go on a weeknight, and at the last showing, when it was the coolest.
Tell you what, though. The winter of '89-'90 MORE than made up for it. I've never been so cold in all my life.