Freezing

Freezing is a game-mechanic which makes surviving Winter (and the heavy rainfall present in Don't Starve: Reign of Giants Spring) more difficult. Whenever a character is away from a heat source for too long they will begin to freeze.

Once the edges of the screen become encrusted with ice (body temperature < 5° for vanilla and < 10 for RoG), this is a warning that the character is close to freezing, and the player should seek a heat source as soon as possible. When a second layer of ice crust forms over the edges (body temperature < 0°), the character starts to take 1.25 damage each second. Freezing stops soon after the player finds a sufficient heat source.

Freezing can be negated by being near a sufficiently warm heat source, slowed by wearing warm Clothes, growing a Beard or stopped for a limited time by carrying a charged Thermal Stone or equipping a Torch.

Fire
The best way to have a reliable and steady source of fire is by having a Campfire, Fire Pit or a Star. A Torch won't provide much warmth but can buy a limited amount time before freezing actually settles in.

In emergencies, objects and even creatures can also be set on fire for an immediate source of warmth. A single flammable item can be dropped on the ground by holding the CTRL key and clicking the LMB. Once on the ground such items can be lit on fire with a Torch, and will provide a small and limited amount of heat. With enough fuel, small fires like this can provide enough warmth to get to a better source of heat. This might be dangerous (or advantageous) however as nearby flammable objects can catch fire as well.

Clothing
One of the best options for traveling away from a fire during winter is to wear some combination of warm clothing. These items increase the amount of time a character can be away from fire before freezing begins. Having several items equipped at the same time provides a cumulative bonus. Sooner or later however, characters will be forced to return to a source of warmth, as wearing insulation merely delays freezing.

Food
The following Foods will instantly increase body temperature:
 * Meaty Stew - +25°
 * Spicy Chili - +20°
 * Dragonpie - +10°
 * Honey Ham - +5°
 * Stuffed Eggplant - +5°

Other

 * Thermal Stones can be used to store heat.
 * Wilson's and Webber's Beards provide additional insulation depending on their length.
 * Willow's Lighter produces a very small amount of heat by itself, but in a pinch could be used to light surroundings on fire for emergency heat.

Mechanics
Freezing mechanics are based on the temperature implementations in the game. Body temperature ranges from -20° to 40°. Any time body temperature falls below 0°, the character will take 1.25 damage per second.

Ambient temperature is a key factor influencing a character's body temperature. Body temperature will attempt to match the ambient temperature, this rate is called the Ambient Delta.

Ambient delta can be any value between +5 and -1. It is given by the function:

Total insulation is the sum of all insulation worn by the character (see table below).

Ambient Delta takes into account the total effect of all heat sources affecting the player (including weather, campfires, Thermal Stones, and lit torches), and is also a function of the player's current temperature.

The Net Temperature Effect of a heat source depends on its distance from the player and its raw source temperature (listed in the Heat Sources table below), referred to as its Source Temperature:
 * if the source temperature is positive and above the player's body temperature, it will contribute to the ambient delta
 * if the source temperature is positive but below the player's body temperature, it will have no effect.
 * if the source temperature is negative (e.g. it is a "cold source" such as the Chilled Amulet), it will contribute (negatively) to the ambient delta.

In other words, the Net Temperature Effect for each source is given by the equation:

The starting point for the Ambient Delta is the current air temperature, as determined by the weather.

For each heat source, the player's body temperature is first subtracted from the heat source's Source Temperature, and then added to the Ambient Delta. Carried or equipped heat sources have a Source Temperature equal to its Raw Source Temperature. For environmental heat sources (e.g. fireplace), Source Temperature will decrease as the distance between it and the player increases.

If the Ambient Delta is greater than 0 (i.e. the environment is warmer than the player's current body temperature), then the maximum increase of the player's body temperature will be +5° per second while the player's body temperature is below the freezing point (0°), and +1° per second once the player's body temperature is warmer than the freezing point. Note that the increase of the player's body temperature cannot exceed the Ambient Delta, so the actual rate may be smaller than +5° or +1°.

The final equation for calculating Ambient Delta is given here:

Where Warming Cap is 5 if the player's body temperature is below 0° and 1 if the player's body temperature is above 0°.

Insulation only becomes a factor if the Ambient Delta is less than 0 (i.e. all ambient heat carried and in the environment is still colder than the player's body temperature), in which case it operates per the Ambient Delta formula above. Insulation provides exponentially less and less protection from cold, so the first item worn makes the biggest difference by far.

For the purpose of calculating a Thermal Stone's own temperature loss, a fixed insulation of 120 is used. This value is not added to the player's total insulation, nor does the player's insulation affect the Thermal Stone in any way. A Thermal Stone cools at the same rate on the ground as it does in the inventory.

For full list of burnable objects see Fire.

Trivia

 * Thermal Stones only work while their temperature is greater than the player's body temperature; once the Thermal Stone cools to below that level, it has no further effect on the player's body temperature.
 * The warmest combination is a Puffy Vest, Beefalo Hat and fully grown beard (if you are Wilson). This will add up to a whopping 615 points of insulation and would take 16.67 real time minutes to freeze (with a fully charged Thermal Stone).
 * With a fully charged Thermal Stone and a Torch equipped, it is possible to have a mobile heat source almost as hot as a stage 1 Campfire.
 * Torches only emit heat when equipped (as one would expect), although they appear lit in inventory.
 * Hypothermia is a loss of body heat due exposure to cold or freezing water and can cause death.
 * Frostbite (or frostburn) is a cold injury which commonly occurs at the soft tissues in the hands, feet, and nose due to severe freezing.