The SI unit for Temperature is Kelvin (K). However, Celsius is also often used as a measure of temperature. The formula to convert Celsius to Kelvin is K = C + 273.15. So 25 degrees Celsius will equal to 298.15 Kelvin. 25 degrees Celcius or 298.15 Kelvin is called normal temperature.
Atkinds, Peter. Physical Chemistry. 9th. Oxford University Press, 2009. Print.