OBJECTIVES: This study aimed to analyse if there were any associations between patulous Eustachian tube occurrence and climatic factors and seasonality. METHODS: The correlation between the monthly average number of patients diagnosed with patulous Eustachian tube and climatic factors in Seoul, Korea, from January 2010 to December 2016, was statistically analysed using national data sets. RESULTS: The relative risk for patulous Eustachian tube occurrence according to season was significantly higher in summer and autumn, and lower in winter than in spring (relative risk (95 per cent confidence interval): 1.334 (1.267-1.404), 1.219 (1.157-1.285) and 0.889 (0.840-0.941) for summer, autumn and winter, respectively). Temperature, atmospheric pressure and relative humidity had a moderate positive (r = 0.648), negative (r = -0.601) and positive (r = 0.492) correlation with the number of patulous Eustachian tube cases, respectively. CONCLUSION: The number of patulous Eustachian tube cases was highest in summer and increased in proportion to changes in temperature and humidity, which could be due to physiological changes caused by climatic factors or diet trends.