Trends of Minimum and Maximum Daily Temperatures in Italy from 1865 to 1996

Annual and seasonal changes in maximum and minimum temperatures (Tmax and Tmin) and in daily temperature range (DTR) in Italy are investigated. Monthly average series for northern and southern Italy are analysed for evidence of trend. Tmax and Tmin show a positive trend over the period 1865–1996 which is greater in southern Italy than in northern Italy. DTR shows a positive trend, but greater in the North than in the South. There is a positive correlation between DTR and mean monthly temperature especially in spring and in summer, while there is a high significant negative correlation between DTR and monthly precipitation. Analysis of temperature, precipitation and DTR during the period 1865–1996 suggests that a general relationship between the very warm last 15–20 years and an increase in the frequency of sub-tropical anticyclones over the Central-Western Mediterranean. This relationship is based on the hypothesis that in Italy more frequent sub-tropical anticyclones could have been the most characteristic feature of the warm periods during the last 130 years.