I have been using the Thermarest Neo Air Xlite for lightweight trips in all seasons except winter. This Mat has an R value of 4.2 which means that it technically fits into the category of winter use, however I find the narrower shape and rounded corners lets in a bit to much cold air for me. Slimmer hikers may find it comfortable in winter conditions. The R Value is basically a measurement of a materials ability to resist heat transfer. For example, your body warmth to the ground or the grounds temperature to you.
|Winter||4 and above|
This mat represents awesome warmth for its 340grams and takes up very little room in the pack. I will pack this mat, my quilt, Nemo Hornet 2P tent and stove and essentials into a 40l pack for overnight hikes in warmer weather.
I do find this mat slightly too narrow, however they do offer a large version of the mat which comes in at 460g and is considerably longer and wider.
If you are looking for a great value mat that can see you through most conditions then this is definitely a mat worth adding to your list.