According to a study by researchers from the Pablo de Olavide University of Seville, the Complutense University of Madrid and the Institute of Geosciences of the CSIC, certain factors such as global warming caused by climate change and the Multidecadal Oscillation of the Atlantic have contributed to the Summer has stretched since the late 1970s in Europe to an average of about six days per decade.
The research analyzes the so-called multidecadal variability of the start and end dates of summer as well as the length of summer. To accurately calculate the time when summer weather begins and ends, experts have created an algorithm based on local temperature thresholds that they have applied to the E-OBS database, formed from daily data collected in observatories throughout Europe during the period 1950-2012. The results reveal an average lengthening of the summer of 2.4 days per decade for that period 1950-2012. However, the trend varied in the period after 1979, when the elongation reached values of between 5 and 12 days per decade, especially in western Europe and the Mediterranean region. These changes coincide with trends towards rising temperatures observed during the months of June and September in Europe, which affect the start and end dates of summer.
