With a guitar it is most important that you keep it at normal temperatures, when you expose your guitar to really high temperatures the wood might start doing weird things. Luckily it can be fixed most of the time but it's really better for the durability to keep it in a normal temperature environment. That would be 'normal room temperature' so 15 to 25 degress would be ideal.
Read this article if you want to know a bit more. http://en.wikibooks.org/wiki/Guitar/Guitar_Maintenance_and_Storage
I wouldn't call Afghanistan ideal with temperatures above 40/50 degrees. Keep that in mind.
JJ