@Grivusangel -- That meteorologist was probably one who looks more at dewpoints. That's the "second" temperature you see that indicates how saturated the air is for the temperature. The closer the dewpoint is to the actual air temperature the more humid it is -- and often, the more unstable the air is. Dewpoint is a big factor in determining the possibility of severe weather in a given area.
By the same token, during the winter, the dewpoint is often a good predictor of how low the temperature will drop overnight. The lower the dewpoint, the lower the temperature will likely go, since dry air doesn't hold heat nearly as well.
Still, relative humidity is, as you say, a good indicator for the average person of how muggy the day may be.