What's the comfort temperature rating of your sleeping mats? Why don't you publish a temperature?

All Sea to Summit sleeping mats are tested for R-Value in ASTM-certified labs.

Taking an R-Value and relating it to (air) temperature is a complex and possibly misleading exercise, so Sea to Summit does not publish a temperature 'rating' for its sleeping mats.

Here are some of the challenges in calculating a 'temperature rating' for sleeping mats:

• The temperature you would need to know is the ground temperature. Weather information only reports the air temperature - the ground may be much colder than the air (which is how dew or frost forms)
• Humid air / damp ground conducts warmth better than dry air / dry ground (which is why 'damp cold' feels colder than 'dry cold' at the same temperature)
• In winter, sleeping on rocky ground without snow will always be colder than sleeping on snow at the same air temperature. Snow insulates.
• A live sleeper on an unstable air-filled sleeping pad may move a relatively large amount of air inside the pad This dissipates the warmth that the sleeper has introduced to the pad.
  • The above loss of warmth is not reflected in the mat's R-Value, which is tested in a static test.
  • This effect only takes place with certain air-filled pads. Self inflating mats have a foam core and air movement is not a factor. Sea to Summit Air Sprung Cell mats are really stable; so internal air movement is minimal.

A rough guide to linking temperature to R Value is to refer to the likelihood of frost forming, because the formation of frost is linked to ground temperature and humidity. 

• Light frost: Requires an R-Value of 3-4 (or greater)
• Heavy frost: requires an R-Value of 4-5 (or greater)