Temperature Tolerance

Cost: 1 point/level

Temperature Tolerance is a mundane physical advantage.

http://www.sjgames.com/gurps/faq/FAQ4-3.html#SS3.2.21 talks about how Immunity to Metabolic Hazards of Resistant covers some of the same ground.

Having both doesn't appear to give any kind of discount though.

By Default

By default rules, Temperature Tolerance gives a creature a wider "comfort range" of temperatures.

In the Dungeon Fantasy RPG

Temperature Tolerance is streamlined for DFRPG. It adds directly to HT whenever you roll to resist temperature-related effects (mainly, when avoiding fatigue or injury from extreme climates). It provides no damage resistance but does help resist any temperature-related effects that require a HT roll, such as fatigue damage from intense heat or cold. One level of Temperature Tolerance is fairly easy to justify for any character build, but is most common among fluffy catfolk or nature-enduring barbarians.

In Underground Adventures

Underground Adventures presents alternative rules for extremely high Temperature Tolerance levels necessary for their Crystalloid Races to survive outside of the planet's core. In this, the comfort zone for the Crystalloids are determined by multiplying the standard 55ºF zone by the average temperature of the Crystalloid's comfort zone (9,460º) with respect to absolute zero divided by the average of the Human comfort zone (522º) with respect to absolute zero (55 x (9460/522)), which is roughly 55 x 18. This gives a range of 8,505ºF to 9,495ºF and means each point of Temperature Tolerance adds HT x 18º to their comfort zone as well.