It is not at all uncommon to hear that a patient feels well or ill parallel to changes of the weather. There is no doubt that barometric and above all hygrometric changes produce distinct and often marked variations in sensation. Probably no information, however, is more fallacious than the vague general impressions with regard to these effects of the weather that are supposed to be common knowledge. For instance, it is a shock to most persons to learn that though dark, rainy days are supposed to produce depression, and bright, sunny weather to lift clouds of despondency, suicides are most frequent in June and least frequent in December. Cold weather is supposed to be a great source of suffering and consequent depression, especially to the working classes, and yet the cold winter months have fewest suicides and the warm summer weather the most. It is not the extremes of heat, however, which produce the despondency and ill feeling that lead up to suicide, for the climax of the curve of suicides is not reached in July or in August, when people have become run down from the persistence of hot weather, but in the pleasant month of June.
The Effects of Weather on Pain, Comfort and Efficiency. JAMA. 2015;313(8):861. doi:10.1001/jama.2014.11604