What was London’s average maximum summer temperature in the early 1970s?

Summer temperatures in London have risen more over the last 30 years than in any other European capital city, according to a new report. The study shows that London’s average maximum summer temperature has jumped from 20.5OC in the early 1970s, to 22.5OC over the last five years, a rise of two degrees. Across the 16 capital cities, 13 have risen by at least 1℃ over the last 30 years. The report by environmental group WWF, says that climate change will increase the likelihood of more frequent and intense heat waves, droughts and rainstorms.