From the Guidelines

Yes, standing in morning sunlight can effectively align your circadian rhythm, as evidenced by the most recent study in 2022 1.

The study found that morning sunlight exposure, which contains blue wavelengths, can suppress melatonin production and signal the brain's suprachiasmatic nucleus that it's daytime, helping to regulate the sleep-wake cycle.
The American Academy of Sleep Medicine clinical practice guideline from 2015 1 also supports the use of morning light exposure to align the circadian rhythm, although it notes that the evidence is limited.
Another study from 2022 1 highlights the importance of minimizing evening light exposure and using interventions such as blue-light-blocking glasses or shifting screens to warmer colors to reduce short-wavelength light exposure.

Aim for 10-30 minutes of direct morning sunlight exposure, ideally within the first hour after waking.
No special equipment or medication is needed—simply step outside without sunglasses to allow light to reach your retinas.
Combining this practice with consistent sleep and wake times will further strengthen your circadian alignment.
Consider using blue-light-blocking glasses or shifting screens to warmer colors in the evening to minimize disruption to your circadian rhythm.

From the Research

The relationship between standing in the morning sun and circadian rhythm alignment is supported by studies on the impact of light exposure on the human circadian system 2.
Morning light exposure has been shown to affect the circadian phase of melatonin levels, which is a key regulator of the body's internal clock 2.
The timing of light exposure is crucial, as exposure to light in the morning can help regulate the circadian rhythm, while exposure to light in the evening can disrupt it 2.

The suprachiasmatic nucleus (SCN) plays a key role in regulating the circadian rhythm, and light exposure sends signals to the SCN to synchronize the clock with the light-dark cycle 3.
Other inputs, such as food intake, exercise, and temperature, also affect the clocks in peripheral tissues, including the skin 3.
The core clock network interacts with fundamental physiological processes in the skin, including homeostasis, regeneration, and immune- and stress responses 3.

While standing in the morning sun may help align the circadian rhythm, it is also important to consider the potential risks of UV radiation exposure, which can cause skin damage and increase the risk of skin cancer 4, 5, 6.
The skin's natural protections against UV damage may be affected by lifestyle changes, including changes in sun exposure and the use of sunscreens 6.
Melatonin, a hormone involved in circadian regulation, also plays a role in protecting the skin from UV damage 6.