We can not say a general overall climate for Turkey.
Marmara region; Istanbul and around the Sea of Marmara the climate is moderate
Winter: 3 to 10 deg.C (the temperature can drop below zero sometimes)
Summer: 27 to 35 deg.C
Aegean region;
Winter: 9 to 15 deg.C
Summer: 29 to 40 deg.C.
Mediterranean region climate is similar to Aegean region climate.
Central Anatolian region;
There is a great temperature difference between day and night. Rainfall is low and there is more snow.
Summer: around 23 deg.C
Winter: around 2 deg C
Black Sea region
Summer: around 23 deg.C,
Winter: around 7 deg.C
Eastern Anatolia and South-Eastern Anatolia
Long hard winter, where year after year snow lies on the ground from November until the end of April Winter: -13 deg.C
Summer : 17 deg.C).