Temperature

Temperature is a status that applies in two areas of the game: Inferno Cave and Polar Fields. Spending time in either location's 'Wild' area requires either the Flame Retardant Suit or the Warm Clothing, respectively. Even with this clothing, the slider will gradually approach the left end or the right end. Reaching either extremity of the gauge will cause the player to quickly lose health, similar to the effects of Poison but faster. This can be prevented by utilising Water Pools and Hot Springs, respectively, to cool down or heat up.
When the player enters the entrance/village area of either location, the Temperature scale will become visible, but the slider will not move. It will only begin moving once the player opens the area's door to enter the wild area. There, the slider will move left or right one tick approximately every three seconds, After about a minute and ten seconds (Inferno Cave) or 45 seconds (Polar Fields), the fire or snow-dog icon will glow, signaling that the player will soon take damage from overheating or frostbite. After about a minute and thirty seconds total (Inferno Cave) or 1 minute total (Polar Fields), the icon will grow brighter and pulse, the player will begin quickly taking damage, about one half of a heart every half second. Players can adjust their temperature and avoid damage by using Water Pools and Hot Springs. Water Pools quickly snap the player's temperature back to the base, center value. Hot Springs are slightly more time-consuming, gradually raising the player's temperature as they stay in. They allow the player to exit once their temperature reaches its base value, which takes a maximum of about 10 seconds. However, the player can stay in to put their temperature on the opposite end of the scale, increasing the maximum amount of time they can explore without needing to return. This additional temperature raise is slower, taking about 15 seconds to raise a player to the Hot Spring's maximum. The fire icon will glow in its first stage at this point, but the player will never take heat stroke damage from staying in too long. If the player raises their temperature as high as possible in a hot spring, the snow-dog icon will take around a minute and 35 seconds to glow, and the player will start taking damage after about a minute and 50 seconds, total.
A (part of a) Water Pool may be within the detection range of Bat. While the player is drinking, it will flap near them in the Dangerous state. Once they finish drinking, it will immediately attack. This is still preferable to taking damage from heat stroke, especially since Bats only deal 1/2 heart of damage.
If the player is taking damage from heat stroke or frost bite, activating the prompt to drink water or jump in a hot spring will immediately stop them from taking more damage.
Temperature does not change during cutscenes or actions like Fishing, which makes the latter feasible in Polar Fields.
If a player leaves the 'wild' area of either location and returns to the village area, their current temperature value will be preserved. If they leave to another location entirely and return, though, such as taking the exit to Crystal Caverns and returning, their temperature will be reset to the default value.
If the player attempts to enter either area's gate without the appropriate protective clothing, Beat will recommend they use the appropriate clothing, and the player will be unable to enter. 
=== Trivia ===
The player can choose to unequip their protective clothing while they are in Inferno Cave or Polar Fields. If they do, their temperature will immediately snap to the environment's extreme, unless they are currently drinking water or in a Hot Spring. Further, they will immediately begin taking damage at a rate of about one half heart per frame, giving a near-instantaneous Game Over to even maximum-health characters.
The in-game hints for temperature show a player character with the beginning maximum health of three hearts, but quests will raise the player's health higher by the time they access these areas in-game.