Mostly a country of hills and mountains, Macedonia has a continental Mediterranean climate characterized by long, dry, rather hot summers and short, cold winters. The average air temperature in the summer is 25°C (77°F) and 0.5°C (33°F) in winter. However, short periods of extreme temperatures of 110-115°F in summer and low 20s in the winter are common. The average annual precipitation is 445.5 mm. The humidity in Macedonia averages 66%. Occasionally, there are dust storms in the Vardar River valley. Macedonia is on a fault line and the country averages four earthquakes a year (most go unnoticed) with a median reading of 6 on the Medvedev-Sponheuer-Karnik International Seismological Scale.