Dew points.
Some naturals use different products in their hair depending on dew points outside. One of them will explainit better because I don't pay attention to them nor do I use too much glycerin in my products anyway (coincidence). So I don't want to explain it wrong. But badically, the higher a dew point, the frizzier your hair gets when glycerin's used because it draws the moisture out the air to your hair.

...or the other way around...? O_o

Big Chop: 11/25/09
Cottony/fluffy, medium/coarse, high density & porosity
SL - APL - BSB - BSL - MBL - WL - HL