It's entirely down to you. I have been in much of Iran in Dec / Jan / Feb. It gets quite cold in the northwest, -10C is common, but it's not too bad. It can be quite grey and miserable though. The centre of the country here all the min sights are will be around freezing or few degrees above. It's quite bearable. Homes are heated and always warm, as I imagine are hotels. As far as roads are concerned, snow is certainly not a problem as they re cleared and gritted.
Eastern Turkey gets colder, but I haven't been there in winter, so can't say.
If you're really afraid of the cold, the Persian Gulf coast is lovely and warm through the winter.
Daniel, Ulaanbaatar, -11C
|