Not so hot also is a way of saying that you do not really like something.

VOA: special.2009.12.06

They could better handle hot,dry climates because they do not have a lot of wool.

VOA: special.2009.08.03

Do this when the weather is not too hot and not too cold.

VOA: special.2009.04.28

They were not hot enough -- like stars-- to give off light.

VOA: special.2009.04.29

A hot spot does not move.

VOA: special.2010.01.12

Another expression is not so hot.

VOA: special.2009.12.06