This will vary, depending on the type of holiday you would like to have, and the region you are planning to visit. Since Turkey is a heavenly place for holidays all four seasons, you can find yourself a suitable season in any case.
For beach and sightseeing holidays the recommended seasons are spring and autumn; roughly from April to June and September to October. The climate during these periods on the Aegean and Mediterranean coasts is perfect for sunbathing when there are fewer crowds and the weather is hot but not annoying. Istanbul is also at its best during these days while Central Anatolia is cooler and perfectly suitable for sightseeing and touring.
The season for the ones who prefer a sunbathing and watersports holiday is from May to September. The best months are, of course July, August and September. The water temperatures are the warmest during these months. The Mediterranean and South Aegean coasts, generously display all the opportunities for a perfect watersports holiday during this period.
If you would like to venture through the wonders of Eastern Anatolia, it is advisable to do it in May, June, September and early October so that you may wander comfortably without being irritated by either cold or desert heat.
The Black Sea Region also offers you possibilities of sightseeing and natural beauties which you would not like to miss. The best season for swimming is from June to early September which are the hottest months in this region. If you are planning a visit in other months, be ready for rainfalls which are heavier during the winter season.
If you are planning a winter sports holiday, you will find here more than you expect. Forested mountains of heights between 2,000-2,500 meters, are the locations of many Turkish winter sports centers. Some of the most popular resorts are; Uludag, 36 km south of Bursa in the Marmara Region; Kartalkaya 50 km to Bolu; Saklikent located 50 km northwest of Antalya on the Mediterranean coast; Palandoken near Erzurum, Sarikamis near Kars, Erciyes near Kayseri in the Eastern Anatolian region. Early December and early March are best for winter holidays in Eastern Anatolia since the weather conditions are hard and troublesome in midwinter, and may cause some unpleasant surprises, like having all the roads closed because of heavy snowfalls.