BACKGROUND: Seasonal variation in exacerbations, hospitalisations, and mortality statistics has been reported for some diseases. To our knowledge, however, no published studies exist on the seasonality of health-related quality of life (HRQoL) amongst rhinologic patients. AIMS/OBJECTIVES: This study, therefore, aimed to investigate the possible seasonal variation in rhinologic patients' HRQoL using the rhinologic disease-specific Sino-Nasal Outcome Test-22 (SNOT-22) and the generic 15D HRQoL instrument. MATERIAL AND METHODS: We enrolled unselected adult rhinologic patients requiring specialist care at the Helsinki University Hospital in this cross-sectional, questionnaire-based prospective study during four seasons: February (winter), May (spring), August (summer), and November (autumn). Patients received SNOT-22 and 15D questionnaires via post. The Finnish Meteorological Institute supplied climate data from these months. RESULTS: SNOT-22 and 15D data were available for 301 and 298 patients, respectively. We found no statistically significant differences (p = 0.948) between the mean monthly 15D scores or mean SNOT-22 scales. Furthermore, the mean SNOT-22 subscales did not differ between the monthly study periods. CONCLUSIONS AND SIGNIFICANCE: Our study shows that seasonality did not impact rhinologic patients' SNOT-22 or 15D HRQoL scores. Thus, these questionnaires can be used for follow-up amongst rhinologic patients regardless of season.