By Lale Surmen Aran and Tankut Aran
Istanbul has a moderate climate year-round. It is generally hot and humid from mid-July to mid-August, and it can snow during January and February. The peak-season months (with the best weather) are from mid-April to June and September to October. During the off-season, you can generally find better deals and smaller crowds, the weather is usually good, and all the sights are open. Weather conditions can change throughout the day — especially in spring and fall — but extremes are rare. Summer temperatures generally range from 65 to 85 degrees Fahrenheit (42–60 degrees in winter). Temperatures below freezing and above 90 degrees make headlines. For daily weather throughout Turkey, see www.meteor.gov.tr.
Keep in mind that prices in Istanbul are higher during festivals and holidays such as Easter, Christmas, and New Year's. On holidays, you'll see lots of vacationing Europeans, mostly from Spain, Italy, and France.
Lale Surmen Aran and Tankut Aran are the authors of the Rick Steves' Istanbul guidebook.