The oxidation behaviour of uranium nitride (UN) powder has been examined while allowed to age over a period of 129 days with both oxidation in synthesised air and high temperature water observed. The UN powder was stored in air and in an argon filled glove box (<3ppm O2) to determine if the storage environment would affect the oxidation. Within this dataset, no significant change to the oxidation onset temperature or reaction kinetics was observed outside of measurement uncertainty with respect to the age of the powder.