Quzhou has a humid subtropical climate with four distinctive seasons, characterised by hot, humid summers and chilly, cloudy and drier winters (with occasional snow). The mean annual temperature is 17.31 °C (63.2 °F), with monthly daily averages ranging from 5.4 °C (41.7 °F) in January to 28.7 °C (83.7 °F) in July. The city receives an average annual rainfall of 1,705 millimetres (67.1 in) and is affected by the plum rains of the Asian monsoon in June, when average relative humidity also peaks. The frost-free period lasts 251–261 days. Winds along the Qiantang River valley are predominantly north-easterly and north-east-easterly.