Istanbul has four distinct seasons. The winter months are cold and rainy, and the city is known to get snow that can sometimes be heavy enough to justify schools being closed. Spring can be exceptionally wet, but it also brings a riot of colour as flowers, particularly tulips, bloom throughout the city. Summers can be hot and humid to the point where an air conditioner is extremely useful during this time of the year. Autumn in Istanbul, on the other hand, is mild.