Sleeping systems - bags, pads, matts, liners

PS That bag has also been used in warmer climes too. The thing with warm-ish bags in hot weather is that:

• if it's really hot, you don't need a bag anyway
  
• if it's a little hot, you can just take off clothes, and or unzip the bag
  
  

In my mind, bags rated warmer than 0 degrees are either for:

• people who don't like taking their clothes off
  
• people who don't like sleeping in a bag with the zipper undone (with or without clothes, as you will!)
  
• extremely weight-conscious climbers/tourers
  
  

Also, final point, people either sleep hot or cold, and your choice of bag should reflect this.