Depending on where you go, weather can have a severe impact on your travel in Afghanistan.  Because the road and air travel infrastructure is so underdeveloped, winter weather can bring travel to a standstill in the central mountains for days or even weeks.  Summer travel can be quite uncomfortable in the lower areas of the country.

The best time of year to travel in most of Afghanistan is mid April to late May.  During this time, the valleys are green and flowers are blooming, while the mountain peaks are still covered with snow, making for a very photogenic backdrop.  For visiting the Wakhan the best time of year is July and August.   If you are going south, wintertime is best (although the South is dangerous and should be avoided at this time).