The Central England Temperature (CET) is a series of average temperatures representative of a triangular central area of the United Kingdom enclosed by Bristol, Manchester and London. The monthly series began in 1659 and daily figures were added from 1772 to date. The CET is the longest available instrumental record of temperature in the world. The CET series was originally constructed by the late Professor Gordon Manley in 1973, and is now routinely updated by the Hadley Centre. Since 1974 the data have been adjusted by 1-2 tenths °C to allow for urban warming.
The graph shows the rise in the CET over the last three decades. The 1990s decade was nearly 0.6°C warmer than the 1961-90 average.