The nasal cycle is a physiologic phenomenon which is affected by some internal and external agents. This study aimed to determine the changes of nasal cycle in healthy subjects over time. The measurements of nasal cycle were made by using a rhinomanometer during 6 h with 30 min intervals in a total of 18 healthy volunteers. The measurements were repeated after 3 months to detect the alteration of nasal resistance over time. The results for the left and right nostril plotted graphically and then patterns of fluctuation in nasal patency were divided into the four categories as mentioned before in literature. We detected a classic pattern of nasal cycle in 6 of 18 healthy volunteers, noncyclic nose in two individuals and irregular pattern in 10 of them in first rhinomanometry measurements. In second measurements after 3 months, seven subjects exhibited different pattern from that in first examination. One participant who had noncyclic nose 3 months ago transformed to irregular pattern and two subjects present noncyclic nose which showed irregular pattern in first measurements. We strikingly detected the changes in the types and presence of nasal cycles over time and suggested that nasal cycle measurements should be made in extended time intervals.