Temperature

Levels, very cold, cold, neutral, hot and very hot Very cold, slowly fills up hearts with ice texture and when it gets to full it slowly does half of heart damage every 5 seconds. Just cold makes you walk slower but does no damage. Neutral does nothing. Hot slightly dehydrates you making your vision slight narrowed and slightly blurred, very hot makes food give less hunger and makes you walk slow, unless you drink a water bottle, it takes time and fill your hearts up with heat affect, very hot can do damage every 10 seconds when dehydrated and no fire protection, netherrite armour makes you immune to heat. Leather armour makes you more resistant to cold, so cold becomes neutral and very cold becomes just cold. Furnaces, fireplaces and torches also increase local heat around it, water decreases heat in the desert, night time in the desert is neutral temperature. The nether is very hot exept for in soul sand valleys which are just hot not very hot. Gold decrease nether temperature aswell. The temperature levels being -2 1- 0 +1 +2. These don’t include burning or freezing in powdered snow. Being in caves removes cold or heat in the desert and nether. 
temperature affects can be enabled or disabled on world settings.