Frizz is a common hair problem when you live in a hot and humid country like ours. This is because suspended water droplets from the air make your hair swell when they go underneath the surface of your hair. This swelling is what you see as small hair waves or bumps that stick out of a supposedly smooth hair surface.
Aside from humidity, combing your hair also causes frizz because of the friction between your comb and your hair strands. Exposure to sun, wind, and pollution can make your hair frizzy, too.