Changes in temperature extremes over Italy in the last 44 years

Abstract Changes in temperature extremes over Italy from 1961 to 2004 were evaluated on the basis of minimum and maximum temperatures measured by 49 synoptic stations uniformly distributed over the country. A set of extreme temperature indices of the Commission for Climatology/Climate Variability and Predictability (CCl/CLIVAR) Working Group on Climate Change Detection was calculated and statistically analysed in order to detect the presence of trends and quantify the variations of the indices for different time periods. Most of the indices, averaged over all stations, show a cooling trend until the end of the 1970s followed by a more pronounced warming trend in the last 25 years. The net variation of the indices reflects an increase in the extremes of the temperature distribution. Among the most significant results, an average increase of 12.3 summer days and 12.4 tropical nights in the overall 44 years are estimated. No significant differences between northern, central and southern Italy are found for most indices, indicating that the trends originate from large‐scale climate features; however, the largest increase of tropical nights is observed at coastal stations. Copyright © 2007 Royal Meteorological Society