Diurnal phenomena

As a detective working on the case of the crossword clue ‘Diurnal Phenomena,’ my initial thought was that it must be referring to something which occurs on a daily basis. The word ‘phenomena’ immediately made me think of natural occurrences, and thus, I started to brainstorm what types of natural phenomena happen on a daily basis. Then, I thought about the rising and falling of the sea level, which happens twice a day, and realized that this could be the answer. Further investigation showed that tides are indeed diurnal phenomena that occur twice in a day, and it made perfect sense. Tides are affected by the gravity of the sun and moon, and their cyclical pattern makes them occur regularly, fitting the definition of a ‘diurnal’ phenomenon. From this line of thinking, it was clear that the answer to the crossword clue must be ‘Tides.’ The satisfaction of solving the mystery was enough to make me feel like a true detective!