Spatiotemporal Changes in Comfortable Weather Duration in the Continental United States and Implications for Human Wellness

Abstract

We examined the spatial distribution of monthly, seasonal, and annual changes in comfortable weather hours (CWHs) between 1950 and 2011 and explored the relationship between human wellness and the amount and timing of CWHs. Using a thermohygrometric index based on air temperature and dewpoint temperature recorded every three hours from thirty-five U.S. cities, we determined whether changes in human thermal comfort were coincident with warming and more humid atmospheric conditions. We tested for significant trends in CWHs for every season for each city for nighttime, daytime, and total (i.e., night and day) periods. Although approximately 75 percent of the cities did not experience significant changes in CWHs on an annual basis, total changes in CWHs were marked by increases during spring and decreases in summer conditions, with the largest positive changes in CWHs found during spring nights, spring days, and autumn nights and the largest negative changes during summer nights and days. Spatially, increases in CWHs were principally located west of 117°W and decreases in cities east of 81°W. Significant relationships existed between wellness metrics and seasonal and annual CWHs. Greater CWHs during the summer were positively correlated with happiness and well-being and negatively correlated with obesity. These results suggest that further declines in summer CWHs for cities might affect human wellness, as peak optimal weather conditions shift toward spring and autumn months.