Difficulty of a world

Minecraft calculates a world difficulty based on the difficulty and the local difficulty, but it does it in a really weird way, and also some thing can be improved

Local difficulty

It ranges from 0 to 6,75. 

Now, it ranges from 0 to 99, and it's influenced by

• Living time
• Moon phases
• Global difficulty

Local difficulty will affect

• Armored mobs spawn
• Mob events
• Status effects on mobs

Living time

Every 15 days of permanence in an area, the local difficulty will rise by 0.2

Moon phases 

When there is a full moon, the local difficulty will rise by 25% for that night

Global difficulty

Every difficulty will act as a multiplier; Pacific is ×0, Easy ×0.5, Normal ×1 and Hard ×2

Mob damage

Mobs will deal damage based on this formula:

Base Damage+(((100/(100-Local difficulty)/50)×difficulty multiplier)

Mob events

• Pillagers patrols: every 10 points of local difficulty, there will be a 2% more chance of spawning
• Zombie sieges: after 50 points of local difficulty, can happen to player bases, not only villages
• Skeleton horses: have higher chance of spawning per Every 10 points of local difficulty
• Raids: enemies have a chance to have enchanted weapons of 5% per Every 10 points of local difficulty

Local difficulty calculation 

(5+(Living time×Global difficulty))