Daily Association Between Ambient Humidity and Loneliness in Older Adults: The Role of Depressive Symptoms and Marital Status

Background: Population aging and climate change are converging public health challenges, yet how daily meteorological conditions affect older adults’ well-being is understudied. Humidity remains underexplored as an environmental stressor that may influence loneliness. Methods: Data from the ZWÄG 65+ study included 108 community-dwelling adults aged 65+ (M = 73.5 years; 54% female) who completed 14-day daily diaries assessing depressive symptoms and loneliness. Humidity data were obtained from a local weather station. Multilevel modeling examined within-person associations. Results: Higher daily humidity was significantly associated with greater same-day loneliness (β = 1.03, p < .01), persisting after controlling for depressive symptoms and demographics. Depressive symptoms showed robust independent associations with loneliness (β = 2.67, p < .001). Marital status moderated the humidity-loneliness association such that only unmarried but not married individuals reported higher loneliness on days with increased humidity. Conclusions: Results highlight humidity as a potentially overlooked weather-related factor relevant to older adults’ social and emotional well-being and underscore the need for further research on the mechanisms linking daily environmental conditions to loneliness in later life.