Continental Portugal has around 2300 to 3200 hours of sunshine a year, an average of 4–6 h in winter and 10–12 h in the summer, with higher values in the south-east, south-west and the Algarve coast and lower in the north-west. Insolation values are lower in the archipelagos, with around 1600 h in the humid Flores Island and around 2300 h in the island of Madeira and Porto Santo. Insolation in the Selvagens is thought to be higher due to weaker orographic lift and their relative proximity to the Sahara Desert.