Trek Light Gear's hammocks are designed to be breathable first and foremost - it's what makes them comfortable on a summer day and prevents sweat and condensation from building up on the hammock in all climates.
However, Trek Light hammocks are also perfectly suited for hammock camping in any season, whether it's the middle of winter or just a chilly summer night in the mountains. Just as with tent camping it simply requires you to use some additional gear to make sure you stay insulated and sleep comfortably throughout the night.
Check out this post on some of the many things you can do to insulate yourself while sleeping in a hammock in cooler weather:
If you're looking for an underquilt for your Trek Light Gear hammock, check out this page: Compatible Underquilts For Trek Light Gear Hammocks
If you're craving even more detail and hammock camping knowledge, definitely give this Hammock Camping Book a read!