This text is a study on the climate data present in Alta Valsesia. For the research work I carried out, I decided to use meteorological and hydrological data from ARPA Piemonte referring to the Alta Valsesia territory, an area of analysis extending about 700 km2 with an altimetry ranging from 300 to over 4000 m asl.To analyse the data, I used a series of indices created by a group of experts on climate change: the Expert Team on Climate Change Detection and Indices (ETCCDI) together with the World Meteorological Organisation (WMO) have created a series of climate indices that make it possible to analyse phenomena of various kinds.The analysis spans more than 20 years, making this work one of the few in the Italian panorama of such an extended duration.