Weather of Istanbul
Turkey has seven climatic regions. İstanbul is situated in the Marmara region, which includes eastern Thrace and Edirne. It's a countryside of rolling steppeland and low hills with an average yearly rainfall of 668mm (26.3in). Rainfall is highest (between 80mm/3.1in and 100mm/3.9in per month) from November to February; July and August have the least rainfall. Humidity follows the same pattern, with the lowest humidity (under 30%) in July, August and September, and the highest (over 60%) - a bone-chilling damp - in December and January.
The city has hot and humid summers with cold, rainy and sometimes snowy winters. Yearly precipitation for Istanbul averages 870 mm. Humidity is often rather high which can make temperaturesfeel much warmer or colder than they actually are. The average maximum temperature during the winter months varies between 7°C (46° F) and 9°C (50° F). Snowfall is quite common, snowing for a week or two during the winter season, but it can be heavy once it snows. It is most likely to occur between the months of December and March. The summer months of June through September bring average daytime temperatures of 28 °C (82 °F).
The warmest month is July with on the average 23.2 degrees Celsius, coldest January with 5.4 degrees Celsius on the average. The highest recorded temperature in Istanbul is 40.5 °C (105 °F) (August 2000), with the lowest being –16.1 °C (3 °F) (February 1927). The weather becomes slightly cooler as one moves toward eastern Istanbul.
The city is quite windy, having an average wind speed of 17 km/h (11 mph).
Summer is by far the driest season, although there is no real summer drought such as occurs further west, and so the climate cannot be considered truly Mediterranean.
When to travel in Istanbul?
Spring is best, autumn next, then summer, last winter.
Spring (April through mid-June) is prime because the weather is moderate throughout the country, the days are long, and the tourist rush hasn't begun. April can be rainy, though.
Autumn (mid-September through October) is second best with mostly mild weather, but the days are shorter, and rain may begin again in October.
Summer (mid-June through mid-September) is quite hot in five of Turkey's seven distinct climatic regions, though usually rainless, and cool inland in the evenings.
Winter (November through March) is chill and rainy everywhere except the southeast, but with lower prices and fewer tourists.