Due to great differences in terrain, the climate of the province is highly variable. In general it has strong monsoonal influences, with rainfall heavily concentrated in the summer. Under the Köppen climate classification, the Sichuan Basin (including Chengdu) in the eastern half of the province experiences a humid subtropical climate (Köppen Cwa or Cfa), with long, hot, humid summers and short, mild to cool, dry and cloudy winters. Consequently, it has China's lowest sunshine totals. The western region has mountainous areas producing a cooler but sunnier climate. Having cool to very cold winters and mild summers, temperatures generally decrease with greater elevation. However, due to high altitude and its inland location, many areas such as Garze County and Zoige County in Sichuan exhibit a subarctic climate (Köppen Dwc)- featuring extremely cold winters down to -30 °C and even cold summer nights. The region is geologically active with landslides and earthquakes. Average elevation ranges from 2,000 to 3,500 meters; average temperatures range from 0 to 15 °C. The southern part of the province, including Panzhihua and Xichang, has a sunny climate with short, very mild winters and very warm to hot summers.