People often wake up earlier due to sunlight exposure in bedrooms writes Michael Breus, Ph.D., for Psychology Today.
The summer solstice is when the earth is tilted most toward the sun. More technically, it is when the planet’s rotational axis is tilted the most toward the star it orbits (our Sun). It usually occurs in June (this year it’s June 21st). The actual summer solstice day is the longest, in terms of daylight, of the year, except in the North and South Pole where there is continuous daylight that can last for days or months.
It is all about light exposure. When the Earth is farthest from the sun, we get the least light. This affects sleep because light directly affects the production of melatonin. More light means less melatonin; less light, more melatonin. This can also have an effect on depression as well, also known as the winter blues. In fact, during the summer we often see people waking up earlier due to sunlight exposure in the bedrooms. This will have an effect on your biological circadian rhythm.