An analysis of the long climatological series of air temperatures in mainland Portugal in the period between 1931 and 2004 shows that, from 1972 on, there is a general trend towards an increase in the mean annual air temperature near the surface. The warmest of last 74 years was 1997.
The 6 warmest years occurred in the last 12 ones, and 2004 was the 18th consecutive year with minimum air temperature above normal (i.e. above the 1961-1990 mean)