The climate of Italy is the long-term weather pattern in the territory of the Italian Republic. The climate of Italy is influenced by the large body of water of the Mediterranean Seas that surrounds Italy on every side except the north. These seas constitute a reservoir of heat and humidity for Italy. Within the southern temperate zone, they determine a particular climate called Mediterranean climate with local differences due to the geomorphology of the territory, which tends to make its mitigating effects felt, especially in high pressure conditions. Because of the length of the peninsula and the mostly mountainous hinterland, the climate of Italy is highly diverse. In most of the inland northern and central regions, the climate ranges from humid subtropical to humid continental and oceanic. The climate of the Po valley geographical region is mostly humid subtropical, with cool winters and hot summers.