Ok; strange question (IMO).
I've noticed this before, but never really gave it any notice until now.
Is it my imagination, or do planes going through a cloud actually sound louder?
I can think of a few ideas, but I'm not sure how or if they apply.
1) the sound is "trapped", or buffered somehow between the ground and the cloud deck.
2) the water vapor transfers the sound better.
3) the increased water in the jet intake somehow affects performance.