Hair gets frizzy because the cuticles get damaged and no longer lie flat, it is usually caused by chemical or heat damage. Using an intensive moisturiser can help beat frizz, as this smoothes the cuticles flat.
Hair is curly because of the type of cuticules (this is where you hair grows out of your head) peple have. But ‘frizz’ is usually due to damaged hair either lots of chemicals heat or sun or sea etc. A hair as a surface which is kinda like scales on a snakes skin, and heat and damage can cause them to stand up on end and away from each other.. non damaged non frizzy hair lays flat.. some hair products work by laying inbetween the ‘scales’ to make hair feel and appear smoother….
I think anywhoo..hope that answers your Q! I ahte it when my hair gets all frizzy in hot damp weather