Temperature changes in Europe 1900-1935; summer season (JJA)


Surface air temperature changes June-August 1900-1935 estimated as the difference between the simple 11yr means for the periods 1895-1905 and 1930-1940. Longitudes and latitudes are indicated along the axis of the diagram.


Summer (June-August)

The period 1900-1935 is generally in Europe recognised as a period of rapid warming after the end of the Little Ice Age. The summer conditions appear to have been characterised by warmer conditions over most over Europe, with the exception of the Iberian Peninsula and southwestern France. Also an area north of the Black Sea show a cooling tendency during this period. The summer warming was most pronounced in northernmost Scandinavia and Russia. The great warming over this region may suggest that conditions high air pressure and relative little cloud cover became more common towards the end of the time interval. Especially at high latitudes with midnight sun a reduced cloud cover would add to the number of hours with unobstructed direct solar radiation. Conversely, the cooling area over the western Mediterranean may have been affected by an increasing number of cyclones. The general increase of summer temperature presumably had consequences for the length of the plant growing season, as is seen from the table below.

PERIOD 1870-1895 1930-1949 1950-1959
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.