There is a strong evidence of the cities' effect upon the local climate and, in particular, upon temperature, which has a strong impact upon human bioclimatic comfort and health. The study is applied in Vic (Spain), a medium-sized city located at northeastern part of the Iberian Peninsula.

In this study, temporal evolution of summer (June, July, August) temperature trends in Vic are studied. During the course of the last century, a temperature increase was found to have occurred in this city, alongside an increase in the number of nights in which the temperature has reached values higher than 20ºC and a reduction of the diurnal temperature range. In the other hand, a decrease in the number of nights in which the temperature has reached a negative value has also found during the coldest months (December, January, February).

These results are useful for the local energy management. Knowing the temperature behavior into the city during summer and winter could be important, so this might lead in the nearest future to such a potential energy saving on housing heating during winter and a more rational use of house cooling during summer.