Summertime sadness
The other seasonal depression
The majority of people with the form of depression known as seasonal affective disorder experience it during the winter months. But summer depression—or “reverse seasonal affective disorder”—exists and is more difficult to diagnose. Part of the problem is biological—research has shown that too much sunlight can interfere with the production of melatonin and serotonin, which can interrupt sleep and cause mood disorders. And though some like it hot, temps in the triple digits can cause overheating, lethargy and exhaustion, which affects normal routines like exercising and cooking at home. The summer blues also can be psychological, as people struggle with body image issues and compare their experience of the season to that of others. If you recognize some of these symptoms, get out of the heat and out of your head. Be kind to yourself and remember that it will rain again before you know it.
Source: Healthline