The rules on "Extreme Cold" (Dungeon Master's Guide, p. 110) state:
Whenever the temperature is at or below 0 degrees Fahrenheit, a creature exposed to the cold must succeed on a DC 10 Constitution saving throw at the end of each hour or gain one level of exhaustion. Creatures with
resistance or immunity to cold damage automatically succeed on the saving throw, as do creatures wearing cold weather gear (thick coats, gloves, and the like) and creatures naturally adapted to cold climates.
0° F (-17° C) is what they are referring to. But what if a party stays outside for a week in temperatures between 32° F (0° C) and 0° F (-17° C)? That seems pretty cold to me and still could make a normal human suffer from exposure.
Did the game designers produce any errata for this effect? Are there any rules governing extended exposure to such temperatures?
Best Answer
What temperature does is up to a GM, but Constitution checks to avoid exhaustion seem reasonable
The entire section on "Weather" (page 110) from the DMG only mentions a few weather types:
Those are all it mentions, and the section on "Extreme Cold" (page 110) states:
There is also a section on "Frigid Water" (page 110) which states:
This is even more impacting that extreme cold - having you make a save every minute instead of every hour. Perhaps you could use this to say that cold temperatures cause saving throws every 2-3 hours.
This is also supported as the section on "Exhaustion" states:
Unfortunately it never mechanically defines how to determine whether freezing temperatures result in exhaustion and "freezing temperatures" probably isn't a literal term. Regardless exhaustion could very well be used with temperatures between 0° F (-17° C)? and 32° F (0° C), the GM would just have to determine a frequency of the Constitution saves and their DC.
The other place I found mention of temperatures is the control weather spell which states:
However, the spell never goes on to explain what any of these temperatures might do, nor does it mention any source or reference to determine what they do.
This seems to say that it would be left up the GM to determine the effects of weather, be they from this spell or elsewhere.