4 PM sunlight is good for some things, but not others. The intensity of the sun's rays, particularly UV radiation, significantly impacts its benefits and risks.
UV Radiation and Vitamin D Production
Many sources state that UV rays are strongest between 10 AM and 4 PM. [5, Everlywell, EPA, UCSF] During this time, your body produces vitamin D more efficiently. However, while you can still get some vitamin D from sunlight after 4 PM, it's less effective than midday exposure. [Quora, Healthline]
- Benefits: Limited sun exposure, even after 4 PM, contributes to vitamin D synthesis, crucial for bone health and immune function.
- Risks: Even though the intensity is lower, prolonged exposure to the sun after 4 PM still poses the risk of sunburn and long-term skin damage.
Sun Safety Considerations
Regardless of the time of day, sun safety measures remain critical:
- Seek shade: If your shadow is shorter than you are, the sun's rays are most intense. Seek shade during peak hours, including periods around 4 PM. [Johns Hopkins Medicine]
- Protective clothing: Wear wide-brimmed hats and protective clothing to minimize sun exposure. [EPA]
- Sunscreen: Use broad-spectrum sunscreen with an SPF of 30 or higher, regardless of the time of day.
- Timing: Morning or late afternoon sun exposure (before 10 AM or after 4 PM) offers a balance between vitamin D production and reduced UV intensity. [UCSF]
In summary, 4 PM sunlight offers less intense UV radiation than midday, reducing the risk of sunburn but still allowing for some vitamin D production. Prioritizing sun safety measures is crucial regardless of the time of day.
