The original magical item is fresh in my mind, as I just handed out one last night! An assassin had a sickle that was a weapon of warning. It’s a short mishearing from warning to warming. Either way you slice it, such a weapon is probably a great thing to have. You either get an edge when it comes to being surprised and getting in fights, or you have an edge exploring harsh environments. You probably don’t want to combine the two, because then you just get a weapon that lets you know to stay indoors during the summer.
Weapon of Warming
weapon (any), uncommon (requires attunement)
This magic weapon protects you in the harshest of environments. While you have this weapon on your person, you have advantage on any saving throw against exhaustion due to the extreme cold or high altitude. You also deal an extra 1d6 weapon damage with this weapon when attempting to break the ice of non-living icy surfaces. In addition, you and any of your companions within 30 feet of you have advantage on Dexterity (Acrobatics) and Strength (Athletics) skill checks to navigate icy environments. The weapon magically prevents you and any companions within range from freezing to death or being damaged from frostbite.