Introduction
In Turkey there is a noticeable variety of climates, with considerable differences between the areas, and also with some microclimates due to the exposure of slopes and coasts.The coastal areas have generally a mild climate, but the coast of the Black Sea is colder than that of the Mediterranean. The interior has a continental climate, with cold and snowy winters, and hot and dry summers, though nights remain usually cool.Summer is dry and sunny throughout the country, except on the north-east coast. In all the inland and south-central regions, the driest months are July, August and September.(The map which is beside shows the climate zones of Turkey.)

When To Go ?
Your overview of Turkey's best travel seasons is quite detailed! Generally, spring (April to June) and autumn (September to October) are ideal for exploring cultural and historical sites, as the weather is pleasant and crowds are manageable.
For beach holidays, the west and south coasts are best from June to September, though July and August can be quite hot. The north and northeast coasts are better in July and August, but they can experience occasional rain. If you're looking for a balance between good weather and fewer tourists, May and September tend to be excellent choices.

What To Pack ?
In Winter : On the north and west coast (Izmir and Trabzon), and in the south , warm clothes, sweater, jacket, raincoat, umbrella. In Istanbul, warm clothes, down jacket, scarf and hat for cold spells. In Antalya and the south coast, spring/autumn clothes, sweater, jacket, raincoat or umbrella. In Ankara and the plateau, very warm clothes, down jacket, hat, scarf, gloves.

In Summer : on the west and south coast (Izmir, Antalya), light clothes, light sweatshirt for the evening, scarf for the breeze; on the north coast (Istanbul, Trabzon), you can bring a sweatshirt or sweater for safety; in the eastern part of the Black Sea coast, a raincoat or umbrella. In Ankara and the plateau, light clothes for the day, sun hat, a sweatshirt or sweater for the evening; in the eastern part of the plateau, you can add a jacket for the evening. In the south, on the border with Syria, lightweight clothing, of natural fibres, desert turban, possibly a sweatshirt for overnight stays outdoors. To visit mosques, you must have your shoulders and legs covered, and bare feet.