Irkutsk originally has a borderline subarctic climate (K�ppen climate classification Dwc), but since 2000 the city warmed to a humid continental climate (K�ppen climate classification Dwb). Snow cover disappeared earlier, from late April in the 1930s to late March in the 1980s. Discontinuous permafrost depth had decreased from 200m to 100m. Irkutsk is characterized by an extreme variation of temperatures between seasons. It can be very warm in the summer, and very cold in the winter. However, Lake Baikal has its effect, such that temperatures in Irkutsk are not as extreme as elsewhere in Siberia. The warmest month of the year in Irkutsk is July, when the average temperature is +18 �C (64 �F), the highest temperature recorded being +37.2 �C (98.96 �F). The coldest month of the year is January, when the average temperature is?18 �C (?0 �F), and record low of ?49.7 �C (?57.5 �F). Precipitation also varies widely throughout the year, with July also being the wettest month, when precipitation averages 113 millimeters (4.4 in). The driest month is February, when precipitation averages only 7.6 millimeters (0.30 in). Almost all precipitation during the Siberian winter falls as fluffy, low moisture content snow
