Classified as having a hot desert climate (Köppen: "BWh"), temperatures during the summer months are extremely hot. The average high temperature in August is 43.6 °C. Winters are warm with cool, windy nights. The overall climate is arid, and the city experiences very little rainfall, especially in summer, but receives a fair amount of rain in March and April. It is also known to have dust storms during which the dust can be so thick that visibility is under . On 1 and 2 April 2015, a massive dust storm hit Riyadh, causing suspension of classes in many schools in the area and cancellation of hundreds of flights, both domestic and international.