Ten years later the State of Malta became the Republic of Malta. Malta joined the European Union in 2004 and adopted the Euro four years later. Malta is the largest island in an archipelago in the central Mediterranean, some south of the Italian island of Sicily across the Malta Channel. Malta is located east of its sister islands of Gozo and Comino. It lies on the Malta plateau, a shallow shelf formed from the high points of a land bridge between Sicily and North Africa that became isolated as sea levels rose after the last Ice Age. Malta is therefore situated in the zone between the Eurasian and African tectonic plates. Numerous bays along the indented coastline of the islands provide good harbours. The landscape consists of low hills with terraced fields. The highest point in Malta is Ta' Dmejrek, at , near Dingli. Although there are some small rivers at times of high rainfall, there are no permanent rivers or lakes on Malta. However, some watercourses have fresh water running all year round, such as those at Ras ir-Raħeb near Baħrija and at l-Imtaħleb. Phytogeographically, Malta belongs to the Liguro-Tyrrhenian province of the Mediterranean Region within the Boreal Kingdom. According to the WWF, the territory of Malta belongs to the ecoregion of "Mediterranean Forests, Woodlands and Scrub". Some minor islands off the main island of Malta include:  Malta has a Subtropical–Mediterranean climate (Köppen climate classification "Csa"), with very mild winters and hot summers. Rain occurs mainly in winter, with summer being generally dry. According to the International Living, Malta is the country with the best climate in the world. The average yearly temperature is around during the day and at night. In the coldest month – January – the typically maximum temperature ranges from during the day and minimum at night. In the warmest month – August – the typically maximum temperature ranges from during the day and minimum at night. Generally – summers/holiday season lasts to 8 months, starting from around mid-April with temperatures during the day and at night, ending in November with temperatures during the day and at night, although also in the remaining 4 months temperatures sometimes reach . Amongst all capitals in the continent of Europe, Valletta – the capital of Malta has the warmest winters, with average temperatures of around during the day and at night in the period January–February.