July 1983: The hottest month on record July 1983 has the highest CET value for any month in the entire CET series with a CET of 19.5. The hotness of the month was due more to the consistency of the heat rather than anything exceptional like with the last few days of June 1976. Thunder occurred fairly often in the south and west of the UK, 94.8mm of rain fell at Idle Hill in Kent on the 7th. The peak of the heat occurred from the 12th to the 16th, when 32.2C was reported somewhere each day in the UK. Here's some data from that month Heathrow Mean Max: 27.6C (+5.6) Highest Max: 32.8C Bedford Mean Max: 25.2C (+4.6) Highest Max: 31.1C Cardiff Mean Max: 24.9C (+5.6) Highest Max: 30.2C Plymouth Mean Max: 24.0C (+5.0) Highest Max: 31.0C Birmingham Mean Max: 25.5C (+5.0) Highest Max: 30.8C Manchester Mean Max: 24.3C (+4.7) Highest Max: 31.6C Glasgow Mean Max: 21.8C (+3.2) Highest Max: 30.1C Aberdeen Mean Max: 20.4C (+2.9) Highest Max: 25.8C Belfast Mean Max: 21.1C (+4.0) Highest Max: 28.6C