The best time to visit Turkmenistan? Spring and autumn. The worst time? Summer.
Obviously, you do not have to worry about crowds. You just have to worry about the white-hot desert sun.
Breakdown per season
The worst season to visit Turkmenistan is summer. In July and August, expect temperatures to exceed 50°C. Avoid it if you can.
Remember that most of Turkmenistan’s treasures are located in the middle of a tree-free desert. A place like Merv, which you really need to spend at least a few hours in, becomes almost impossible to visit.
One exception is the Caspian Sea coast, which has a milder climate than the rest of the country and can be visited year-round.
Spring and autumn
The most pleasant weather happens in March-April and October-November.
Especially spring is nice: a brief flush of tender blossoms and green grass colours the land, and the Nowruz festival is a high point in the Central Asian calendar.
Winters are mild, thermometers dip just below 0 at night. When dressed properly, December to March is not a bad time to go.
Events and festivals
Note that the bar charts above are averages. Peaks of 60 degrees Celsius have been recorded in summer.
Climate bar charts courtesy of World weather online