Temperature: When a solid dissolves in a liquid, a change in the solid physical state to liquid via melting takes place. Heat is required to overcome the bonds holding the molecules in the solid together. As the temperature increases, the intermolecular bonds can be more easily overcome, allowing more of the solute particles to be attracted to the solvent particles. Therefore an increase in solubility and temperature is very common.
However, in some cases, increase in temperature has very little effect on the solute.
For all gases, as the temperature increases, the solubility decreases. This is due to the fact that the gas molecules move faster when the temperature increases and are able to escape from the liquid. This makes their solubility decrease.
Eg. sugar is dissolved much easier in water when the water is hot or warm. (CK-12, 2012)