Temperature

Temperature is a state applied to the player at all times. Temperature is affected by many factors including location, weather, heating blocks, and clothing. If the player's temperature is too extreme, they will take damage periodically. Temperature is displayed with a GUI icon beside the hotbar.

Damage
If the player's temperature is too high or too low, they will take 1 damage every 200 ticks (20 seconds).

Temperature scale
Temperature is calculated in arbitrary units which are not visible to the player. Instead, the temperature range is displayed with a GUI icon showing one of five states:

Factors
This is an exhaustive list of factors which affect temperature.

Altitude
For every 12 blocks above sea level (y = 64), the temperature decreases by 1.

Day time

 * Between noon and dusk (game times between 6000 and 12000), temperature is increased by 1.
 * Between midnight and dawn (game times between 18000 and 24000), temperature is decreased by 1.

Shade
Temperature is decreased by 1 if the following conditions apply:
 * The player is sheltered from the sky
 * In a biome with base temperature greater than 3
 * Day time is between mid-morning and mid-afternoon (game times 4000 to 8000)

Caves
If the player is at least 10 blocks away from any block exposed to the sky, they are defined as in a cave. When in a cave, all previously listed factors are ignored, and the temperature is set to the global cave temperature of 0.

Clothing

 * Each item of wool or fur clothing increases temperature by 0.5
 * Each item of any other apparel increases temperature by 0.25

Wetness

 * If the player is currently in water or rain, the temperature is decreased by 3.
 * If the player has been in water or rain within 3600 ticks (1 minute), they are defined as wet. When wet, temperature is decreased by 1, and warmth effects of clothing are cancelled out.

Heating blocks
If the player is within 10 blocks of a heat-producing block, temperature is increased by [heat value - distance]. When multiple heat-producing blocks are in range, the highest temperature is used (temperatures are not added together).