Italy is a unitary parliamentary republic in Southern Europe, which, due to its shape, is often referred to as lo Stivale (the Boot). The country has 61 million inhabitants, being the fifth-most populous country in Europe. 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, while the coastal areas of Liguria, Tuscany and most of the South generally fit the Mediterranean climate stereotype. Conditions on peninsular coastal areas can be very different from the interior's higher ground and valleys, particularly during the winter months when the higher altitudes tend to be cold, wet, and often snowy. The coastal regions have mild winters and warm and generally dry summers, although lowland valleys can be quite hot in summer.