Because some monsters can't stay overground during the day or they will set fire it would make sense for them to stay underground.
Since monsters spawn overground more during the night do they spawn underground more during the day?
I know that monsters spawn in low light but I swear half of the time when I'm exploring a cave and there will be no monsters (like during the day, overground), and then the other half I'm being attacked from multiple sides by literal hordes of monsters with no escape (like at night).
So is it safer to explore caves during the night like it is safer to explore the overworld during the day?
Best Answer
Monsters spawn in low light levels only. If the area is above light level 7 monsters will not spawn. Any areas below that level (even down to 1 square) is a valid spawning space for hostile mobs.
When exploring caves, the tunnels you are exploring might not be the only areas within range to create valid spawning spaces.
Mobs can spawn anywhere between 24 and 128 blocks from the player (outside of this range, they instantly despawn). So if you are exploring caves, there is a likely chance that mobs will spawn in another branch of the cave that you are not currently in.
So, to answer your question - Yes, you are more likely to find hostile mobs in caves during the day, but it does not guarantee any specific encounters.