Kalnos said:They can spawn in the rain because the clouds block out the sunlight in the tiles it's raining in. It would also keep monsters that have already spawned alive, which was your case.
Notch said he made so monsters don't spawn when it rains. Only the ennemies "kept alive" should be.
Also I think I found my problem. Would it be possible that it doesn't rain at Peaceful?
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