✅ Prevailing is the best word to describe something that has ‘won’ or superceded other similar things in becoming current and common (the prevailing mood; the prevailing opinion).
✅ Prevalent is the best word to describe something that has spread widely and is now current and common (Coffee shops are prevalent).
✅ Something that is prevailing might have become, or might be becoming, prevalent. However, prevailing implies an element of competition that isn’t present in prevalent (The prevailing political system throughout U.S. history has been the two-party system).
✅ Prevalent deemphasizes the element of competition, or suggests that competition was in the past (High-waisted jeans are now prevalent).
Try using prevalent in a paragraph describing current trends, with the help of Grammar Coach.