OBJECTIVES: Our objective was to evaluate the association of weather factors with the risk of pain exacerbations in people with symptomatic hip osteoarthritis (OA). METHOD: Eligible participants with symptomatic hip OA were instructed to log on to the study website and complete questionnaires every 10Êdays and additionally whenever they considered they were experiencing a pain exacerbation (case period) during the 90 day follow-up. Pain exacerbation was defined as an increase of two points in pain intensity on an 11-point numeric rating scale (0-10) during the follow-up compared with baseline. Each case period was anchored to four control periods within a 35 day interval using a time-stratified approach. Weather data were obtained for both periods from the publicly available meteorological database of the Australian Bureau of Meteorology. We examined the association of weather factors across 72Êh before the index date with the risk of pain exacerbation, using conditional logistic regression. RESULTS: Among 252 participants recruited, 129 participants had at least one episode of pain exacerbation and were included in the analysis. A significant dose-response relationship was found between average daily temperature variation in the prior 72Êh and risk of pain exacerbations (pÊ=Ê0.04 for linear trend). There was no significant association between maximum daily temperature, minimum daily temperature, relative humidity, precipitation, or barometric pressure and hip pain exacerbations. CONCLUSION: The overall results suggest that only daily temperature variation among different weather factors was associated with hip pain exacerbations in people with symptomatic hip OA.