Surface air temperature changes June-August 1935-1975 estimated as the difference between the simple 11yr means for the periods 1930-1940 and 1970-1980. Longitudes and latitudes are indicated along the axis of the diagram.
The period 1935-1975 is generally recognised in Europe as a period of widespread cooling after the temperature peak reached 1930-1940. For the summer period this general notion is supported by the net changes shown in the diagram above. Most of Europe experienced summer cooling, with the exception of an area around the western Mediterranean. This change of summer temperature has consequences for the length of the plant growing season, as is seen from the table below.
|Average length of the growing season at Oxford, central England (range of the decade averages). Growing season is here defined as days with average temperatures above 5.5oC.||255-265 days||270-275 days||265 days|
|Shortest growing seasons at Oxford (shortest each decade)||205-225 days||237-243 days||226 days|
Source: Lamb 1977.