Temperature (Subnautica)

Temperature is an environmental game mechanic that, like Radiation, affects the player. In most circumstances, extreme temperatures are harmful to the player. However, unlike Radiation, the player can also harness heat sources for Energy applications.

Heat Sources
High Temperatures are typically generated by underwater volcanic activity. Such sources of heat include Lava Geysers, which can be found in a few biomes, and Thermal Vents, which can be found in some of the deeper biomes. Certain biomes are also quite hot, such as the Inactive and Active Lava Zones.

Heat Protection
The player starts taking damage from temperatures above 50 °C. One can gauge local temperature if they posses a Thermometer in one of their equipment slots. However, the player's thermal resistance increases to 70 °C  if they're wearing the Reinforced Dive Suit.

To survive any more extreme temperature will require the use of a vehicle, particularly the PRAWN Suit. The PRAWN Suit is especially useful for collecting resources near heat sources that are too dangerous for a player on their own.

Energy Usage
Heat can be used to generate energy for Seabases through the Thermal Plant; because these are external generators that have to be placed at specific locations to work (any source above 15 °C ), the Seabase needs to be close, or otherwise connected via Power Transmitters.

PRAWN Suits can generate energy from heat using the Thermal Reactor upgrade.