The Watanabe-Sassoon Humidity Scale
Developed in 1967 by Japanese meteorologist Isamu Watanabe and hairdresser Vidal Sassoon.
H1: Negligible humidity; no alert.
H2: Light frizzing; individual strands may be out of place.
H3: Moderate frizzing. Permanents may be askew. Bangs curl counter-clockwise.
H4: Severe frizzing. Toupees shift off of their foundations. Waist-length hair bunches at shoulders.
H5: Devastating curling, or “poodling,” of hair. Brylcreem melts. Complete destruction of $100 hairstyles.