Ancient Egyptians identified three seasons based on cycles of the Nile River: inundation, emergence and harvest. In tropical countries, it’s the rain that tends to divide the year in two: a wet and a dry season. Elsewhere the calendar demarcates four seasons: autumn, winter, spring and summer.
But now, researchers at Stanford University have found that human biology, rather than rivers, rainfall or calendars, could be used to determine the seasons. In their study, published in the journal Nature Communications in October 2020, the Stanford researchers discovered our bodies seem to set their own rhythm, splitting the year into two seasonal time periods. Or at least that’s the case if you live in California, where the study was carried out. Since every geographical location has unique environmental conditions, their approach…