However, of course there are best times to visit this beautiful country.
In April for the visitors who want to see Istanbul, there is Traditional Turkish Tulip festival; all the gardens are courtyards are full of bloomed colorful tulips. After April until August Turkey has the best time to travel which is not too hot and too cold. The month of August can be a bit warmer than other months; the effect of humidity can be felt. In contrary to common idea, Turkey does not get too warm, in the hottest day of the year it may go up to 30-35 Celsius, 95 Fahrenheit.
However September and October again would be nice to travel as it cools down a bit and it is the peak touristic season of the country.
The winter time is not also very cold, while in Istanbul it may snow 1-2 weeks in 3 months of period as January February and March. Inland of Turkey may have some snow too. However seeing Cappadocia under snow is another pleasure.