The body is most efficient at making vitamin D at noon and daily exposure is a great way to boost your health. It doesn’t take much sun exposure to optimize your vitamin D levels.
For example, if you live in the UK, just 13 minutes of midday sunlight exposure three times per week during summer is adequate to maintain vitamin D levels. If you live in Norway, one study found that midday summer sun exposure there is equivalent to consuming 10,000–20,000 IU of vitamin D daily. Not only is getting vitamin D around midday more efficient, but it is safer than getting sun later in the day. One study found that afternoon sun exposure may increase the risk of dangerous skin cancers. “Common health recommendations given by authorities in many countries, that sun exposure should be avoided for three to five hours around noon and postponed to the afternoon, may be wrong and may even promote CMM (cutaneous malignant melanoma).