Abstract: Dengue fever is a mosquito–borne disease caused by the dengue virus. Transmission of the virus depends on the presence of Aedes mosquito. Dengue has become a global problem and is common in more than a hundred countries. It is most prevalent in tropical and subtropical regions. It has been a major public health challenge in Sri Lanka in recent years. Mosquito generation and the spread of dengue are known to be influenced by the climate. Identifying the climate factors that affect dengue outbreaks would be helpful to take necessary actions to prevent the spread of dengue. In this paper, we study the climate factors affecting the spread of dengue in the city of Colombo, Sri Lanka from the period of 2010 to 2018.