At room temperature (around 25°C or 298 K), the average speed of oxygen molecules in the air is about 484 metres per second (or 1,080 miles per hour). This high speed is a result of the kinetic energy possessed by molecules due to their constant and rapid motion at higher temperatures.

Remember, temperature is directly proportional to the average kinetic energy of particles in a substance. As oxygen molecules gain more kinetic energy with an increase in temperature, they move faster on average.