The inhabitants of Istanbul enjoy all four seasons. The characteristic weather here is a somewhat cooler version of the Mediterranean climate: a short spring, ideal summer temperatures, a long autumn with blue skies,and a rainy winter... The Bosphorus dons the purple of the Judas-tree groves in the spring. The parks and gardens are decorated with tulips and other flowers. March is a cool, rainy month, but April and May are exactly what one expects of the spring. June is half spring, half summer. An old saying advises one "not to bathe in the sea before you see the rind of a watermelon". It is possible to bathe in the seas of Istanbul until the end of September. In July and August, except for perhaps two or three hot weeks, there are sometimes even cloudy or cool days. The weather can be undependable in a region with such a blending of lands and seas. Morning clouds may clear toward noon and invite the sun. Autumn is the longest season, and during the larger part of the year the morning haze makes the skies as bright as mother-of-pearl. During the winter months from December to March one needs a raincoat, a thick coat, and sometimes even a fur. There are few days of frost or snow. The main winds throughout the year are the cool and rainy "poyraz" from the south, and the warm "lodos" from the south. The last severe winter within the city boundaries was experienced in 1978 when the airport had to be closed partially for three days. For those who long for the snow, the winter sports center in Uludag, Bursa is not far away.

Average annual temperature: 13.7°C (56.6 °F)
Coldest month: February 5°C (41°F)
Hottest months: July-August 22-23°C (72-74°F)
Average annual precipitation: 691mm (27 inches)
Average snowy days: 7

Alongside the efforts involving wastewater infrastructure, the seawaters are in the process of being cleaned and Istanbul is returning to its pre-pollution times of rich bathing opportunities. The beaches on the coast of the Black Sea, the Marmara, and the Princes' Islands are all less than one hour away from the center, and swimming is possible throughout the summer months.

Only experienced swimmers should attempt the currents of the cool Bosphorus. On windy days, the Black Sea is like the ocean. No other city in the world has beaches that are so safe and so close to the city, and seawaters with salt levels to suit every taste. Older inhabitants remember the days when they bathed in the Golden Horn; maybe it will be possible to do so again before the year 2004.