There are several references which say that early morning sunlight would give the best benefits (like this and that). This comes from the common consensus that most of the harmful rays, at that time, are filtered out by a thicker portion of the atmosphere through which the light of the sun must pass through to reach our skin.

Doesn't this theory equally apply to evening sunlight as well. Are there any (notable) differences in the health benefit that one might receive from the early morning sunlight from that of the evening sunlight.

  • 1
    For clarification, I think it would help to add which benefits you are specifically looking for. In the links provided, there are numerous things listed with minimal references to evidence. For example, there are similarities and differences in the principles of light/phototherapy for dermatological conditions, for circadian regulation, for seasonal affective disorder, for Vitamin D3, etc - including safety and efficacy of natural light vs controlled light application. Benjamin A touched on some of these below, but if you are looking for more information, clarification will help.
    – DoctorWhom
    Sep 15, 2016 at 19:02

2 Answers 2


Actually, I am a frequent flyer (I think I spend at least 10% of my year in an airplane or an airport) and I discussed the problem of sunlight with my treating physician.

First, sunlight has an impact on the circadian rythm (which involves the secretion of melatonin, cortisol, control of body temperature) which regulates your wake/sleep cycle.

The effect of evening light was examined in a study where a subject was exposed to several hours of light every evening for a week, and the timing of the rhythms of core body temperature and plasma cortisol were measured.

The authors reported that

Both rhythms were shifted by approximately 6 hours, and examination of temperature data collected throughout the experiment suggested that the shift had already occurred after only 2 days.

Dysregulated circadian rythms (due to impaired melatonin, cortisol and body temperature levels) is associated with many diseases among which psychiatric diseases and metabolic syndrome.

So, this possibly explains the results found in the study you linked on the telegraph.co.uk suggesting that early sunlight might reduce the risk of developing metabolic syndrome, probably because this is associated with a physiological (ie normal) circadian rythm.

Finally, you linked one study regarding "sunbathing is good for you". I think, this should be taken with caution, particularly because increased sunbathing is linked to skin cancer.

We also discussed the effect of different timing of the day to produce the maximum of Vitamin D (I am already deficient...). He mailed me following extracts from this review

Factors that affect cutaneous production of vitamin D3 include latitude, season, time of day, air pollution, cloud cover, melanin content of the skin, use of sunblock, age and the extent of clothing covering the body. When the sun is low on the horizon, the atmospheric ozone, clouds and particulate air pollution absorb UVB radiation, limiting the amount that reach the surface of the Earth. The zenith angle of the sun plays a critical role in vitamin D3 production. When the zenith angle is more oblique, the path length through the stratospheric ozone layer is increased and hence, fewer UVB photons are able to reach the earth’s surface.

So overall, current research evidence speaks in favor of morning sunlight. Evening sunlight might on the contrary be associated with negative effects.

Hope this helps!

  • Then midday sunlight is even better? What is the optimal sun angle? Relationship between sun angle and Vit D produced/second/cm2 of skin accounting for melanin levels will be useful.
    – tejasvi88
    Dec 2, 2021 at 4:07

It is true that there are many benefits from morning sunlight. It helps people who are suffering from vitiligo and white patches. The morning sunlight gives Vitamin D which is good for our body and also for our bones, But there is a specific time in which you have to get exposed to sun and the time is from 7am - 9am. And there is no benefits of evening sunlight.

  • 2
    The first point is quite common around the Internet. Could you cite any scientific data that proves that evening sunlight has no benefit?
    – Ébe Isaac
    Sep 15, 2016 at 11:39
  • 1
    Welcome to health SE :-). We strongly encourage that all answers are backed up with reliable references. It is the only way the readers can assess the merit of an answer regardless of their background. The answers unsupported by references risk being deleted. You can always edit your answer to add resources. Thanks!
    – Lucky
    Sep 17, 2016 at 14:58

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