In this research, two experiments were performed to develop a noncontact measurement method for flow velocity in nasal breathing. On the basis of the results of our preliminary study, we first compared the instantaneous flow velocity of nasal breathing and the air temperature of inhalation and exhalation. Next, we compared the air temperature and the nasal regions on facial thermal images. Results showed that the correlation between flow velocity, air temperature, and the nasal region can be improved using a smoothing filter and our modified normalization procedure.