They will scare you the most during monsoon:

Hair fall : Wet hair is highly vulnerable to damage. So protect your hair from the rains! Wet hair swells, and in this state it is very fragile and therefore it’s easier for hair breakage or hair fall to occur. Brushes have many teeth, which are likely to hit a snag and pull hair to a breaking point. The best way to detangle hair after you shampoo and condition it is by using a wide-toothed comb or pick. Try to avoid using a hair brush until your hair is almost dry.

Dandruff : Increased levels of humidity during the monsoon makes it difficult to manage your hair. Problems such as frizzy hair, dandruff and hairfall become more common as well. But, don’t let the rains get to you. The essential tip here is to regularly cleanse and purify your hair.