A room is maintained at a wet bulb temperature of 25\(^\circ\)C, globe temperature of 30\(^\circ\)C, and air velocity of 0.5 m/s. The decrease in Tropical Summer Index when the air velocity is increased to 3 m/s (in \(^\circ\)C, rounded off to two decimal places) is \(\underline{\hspace{1cm}}\).