All types of waves, including sound waves, can be refracted when they interact with a medium or move from one medium to another. One example of refraction of sound is when the sound of thunder is refracted upwards because of a change in air temperature, from cold to warm.
Sometimes, the sound of thunder is refracted upwards so dramatically that it creates a shadow zone. An observer standing in the shadow zone might be able to see the lightning but not hear the thunder, as the sound waves have been refracted. Similarly, sound can be refracted downwards because of variation in the surface temperature. Downwards refraction of sound is the reason people can sometimes hear conversations from across a lake.