A new study suggests daily outdoor temperatures may influence mood, energy levels and sleep quality, with the strongest effects seen during spring and fall — especially among people living with mood disorders.
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A new study suggests the weather may have an effect on how people feel. Published in the Journal of Affective Disorders, the research found that daily outdoor temperatures are linked to changes in mood, energy levels and sleep quality, adding to a growing body of research examining how environmental factors influence mental health.
The research tracked more than 450 people across multiple seasons. Participants used smartphone surveys to report their mood, anxiety levels, energy and sleep quality multiple times per day. The reports were matched with local temperature data, allowing researchers to observe how fluctuations in weather corresponded with daily well-being.
Even after accounting for factors like light exposure, age, and sex, temperature remained a significant influence on emotional states. The effects were especially notable for people living with mood disorders, such as bipolar disorder and major depressive disorder.
“Humans are part of their environment,” said Dr. Debangan Dey, now an assistant professor in the Department of Statistics at Texas A&M University, who contributed to the research as a visiting fellow at the National Institute of Mental Health’s Intramural Research Program. “Environmental factors like temperature and light affect us, and understanding those connections can help us better understand mental health.”
The strongest associations appeared during the transitional seasons of spring and fall, particularly among individuals with bipolar disorder and major depressive disorder. In spring, warmer temperatures were associated with better mood, higher energy and improved sleep quality in those groups, while similar patterns were not consistently observed among those without mood disorders.
In the fall, the pattern was more complex. Dey described it as a nonlinear relationship, with both warmer and cooler-than-typical temperatures linked to positive emotional outcomes among individuals with bipolar disorder.
“In spring, the results were more intuitive,” Dey said. “But in fall, we saw that both warmer and cooler deviations from the seasonal average could have positive effects. That’s something we still need to understand better.”
Environmental factors and mental health
Seasonal mental health changes are often attributed to reduced daylight during winter. This research suggests that temperature itself may play an independent role. Understanding those connections may become increasingly important as climate patterns shift.
“As climate change increases day-to-day temperature variability, understanding how environmental conditions influence mental health becomes a growing public health priority,” said Dr. Kathleen Merikangas, a distinguished National Institutes of Health investigator and the study’s principal investigator
In the future, environmental data could potentially be incorporated into digital mental health monitoring systems. Because weather patterns can be predicted in advance, researchers say that information could eventually help clinicians anticipate higher-risk periods for individuals with mood disorders.
Expanding the research
The study is part of a broader effort to understand environmental factors that influence human health.
As part of that effort, smartphones and wearable devices are making it increasingly possible to collect real-time environmental data alongside behavioral indicators. These tools can track physical activity, sleep and light exposure, allowing researchers to better understand how people interact with their surroundings on a day-to-day basis.
At Texas A&M, Dey is exploring related work with Dr. Tyler Prochnow, assistant professor at the School of Public Health, whose SPACES Study (Social and Physical Activity Contexts in the Environment in Summer) examines how social networks and built environments influence physical activity and mental health among youth. The study follows middle school students over a one-week period, combining real-time smartphone surveys with wearable devices to track activity patterns and environmental exposures.
“Our goal is to integrate data on temperature, light exposure, air pollution and green space with digital health technologies,” Dey said. “By combining that environmental data with behavioral and physiological information, we can better understand how daily environments shape well-being.”
More information: Associations between daily outdoor temperature and subjective real-time ratings of emotional states and sleep in mood disorder subtypes
DOI: 10.1016/j.jad.2025.120918
https://www.sciencedirect.com/science/article/pii/S0165032725023602
Journal information: Journal of Affective Disorders