Observed Changes in Maximum and Minimum Temperatures and Daily Temperature Range in the Iberian Peninsula and Balearic Islands Between 1952 and 2022

ABSTRACT Based on a dense series of temperature data from 3685 observatories located in peninsular Spain and on the Balearic Islands, the patterns and trends of the annual and seasonal values of the maximum, minimum and daily temperature range for the 1952–2022 period are analysed. To this end, this study analyses anomalies for the 1961–1990 period, trends in different time windows, spatial variations, and the influence of altitude and longitude on the three aforementioned variables. The main results are: (1) since the 1980s, positive anomalies of maxima and minima have been observed, with increasing values in recent decades; (2) summer and spring are the seasons with the highest maxima and minima anomalies, while a decrease in the diurnal temperature range values in autumn has been noted in recent decades; (3) since the 1970s, there has been a positive trend in maximum and minimum temperatures that, after a pause in the 2000s, regains strength given the high values recorded in recent years; (4) the trend in maximum temperature increases with altitude, with stations above 1500 m being the most affected. However, for minimum temperatures, urban stations below 250 m show the most marked trends; (5) the stations in the east are warming more quickly than those in the west. The high temperatures recorded in recent decades have led to a new upturn in temperature trends in the study area, which underlines the importance of regularly updating such studies. The influence of the increasingly warmer Mediterranean Sea may explain some of these changes.