More than half of Bulgaria is hilly or mountainous, with the average elevation about 480 metres (1,575 feet). The Balkan Mountains, which stretch across the country from the northwest corner to the Black Sea, form the watershed between the Danube and the Aegean Sea. The north side of the mountains slope gradually to form the northern Bulgarian plateau, ending at the Danube. A series of narrow plains extend along the central portion of the south side of the range. The broad, irregular Rhodope Mountains delineate the border with Greece to the south. In southwest Bulgaria are the Rila Mountains, where Musala, the highest point in the Balkans, rises 2,925 metres (9,596 feet).The country benefits from a temperate continental climate with clearly marked four seasons. Its summer is hot but rarely sweltering, in winter there is abundant snow and the spring and autumn are beautiful transitional periods. There are regional variations: north of the Balkans, is on the whole more continental; the South West and South East are marine or Mediterranean and have mild winters. There are never droughts, but rain falls usually in more intense bursts than it does in the British Isles.
There are more than 300 sunny days per year throughout the country. The average temperature from April throughout September is 23C. Most of Bulgaria has a continental climate. A Mediterranean climate, with dry summers and mild, humid winters, prevails in the valley of the southwestern Rhodope Mountains and influence is felt in the more southerly regions and Black sea coast; the northern limit of the climatic zone is the Balkan Mountains. Winters can be cold in other parts of the country, hence its popularity as a destination for skiers.