Presence of high intermolecular interaction leads to the appearance of Viscosity.

As the temperature increases, it leads to weakening the intermolecular forces operating between its particles(because increasing the temperature leads to increases in the vibration of bond and due to rapid vibration bond strength decreases and as also kinetic energy of molecule is increased due to which the interaction is decreased).Hence, as the temperature increases viscosity decreases because the viscosity is decreases when the intermolecular forces operating reduced.

Hence, as the temperature increases the viscosity decreases.