It’s official – the summer solstice has passed and the days are incrementally getting shorter. Now that we celebrated the day of the year with the most sunlight, it’s time to be aware that sunsets are getting earlier and sunrises are later each day. Remember that the sunlight is the basis for our sleep-wake cycle. Anyone who relies on the sun to wake up needs to understand how sunrise times change each day and how that affects their schedule.
For example, the earliest sunrise comes about one week before the June solstice along the middle latitudes (1). Around the summer solstice, the sun will rise later and set earlier each day due to the rotation of the sun around the earth and our shifting tilt. Look at the differences between sunrise and sunset in Coralville, Iowa from the summer to the winter solstice (2).
- June 20, 2021: sunrise at 5:30am and sunset at 8:45pm
- December 21, 2021: sunrise at 7:30am and sunset at 4:40pm
That’s a difference between 15 hours of daylight on the first day of summer to 9 hours on the first day of winter! Every six months, we gain and then lose six hours of daylight. However, this is a slow process.
For example, the Washington Post carefully monitored the sunrise in D.C. for the first 11 days of January 2015 (3). They saw that sunrise stayed consistent at 7:27am, making everyone’s morning commute in total darkness (3). It’s why even though we start to have longer days in January, it doesn’t feel that way because the extra light is only at night and not in the morning.
So how does this knowledge affect your daily wakeup routine? People who rise with the sun may be late to work if they are scheduled before 5:30am in the summer or before 7:30amin fall and winter. It can be really frustrating and stressful when our schedules don’t match how our circadian system is affected by sunshine.
One thing that can help when you need to wake up before sunrise is using an artificial light that mimics daylight. The illumination provided by the Light Awake app can help stimulate your brain at any time of year. Even as sunrise changes every day, Light Awake will help you rise at the right time.
For more wakeup tips, read my post on 5 Reasons Why You Should Have A Morning Routine.