Blog | When Can I Get Vitamin D from the Sun? 🌞

There are many familiar signs of spring, blooming buds on trees, snowdrops pushing through the soil, and longer daylight hours. But one of the most important seasonal changes is something we can’t see: the return of natural vitamin D from the sun.

Unlike the more obvious signs of spring, the return of vitamin D is a little more subtle.

In the UK winter months, the sun never rises more than 30 degrees above the horizon. Because of this lower angle, sunlight passes through more of Earth’s protective atmosphere, which filters out UVB rays, the key ingredient needed for vitamin D production.

This means that for several months each year, our bodies simply can’t generate vitamin D from sunlight alone.

To make up for the winter vitamin D deficit, it’s important to maximise sun exposure during the months when UVB rays are available.

The exact dates vary by location, as seen below:

London: Available March 1st to October 12th
Birmingham: Available March 3rd to October 9th
Manchester: Available March 6th to October 7th
Newcastle: Available March 10th to October 3rd
Edinburgh: Available March 12th to September 30th

At the start of spring, vitamin D synthesis is only possible for a short window around midday (approx. 11:45 AM – 1:00 PM), as the sun barely clears the 30-degree threshold. However, this period increases until the summer solstice (June 21st), when UVB exposure peaks. From that point onward, it begins to decline again as we move toward autumn.

This seasonal shift provides a crucial opportunity to optimise healthy time outdoors and make the most of natural vitamin D production.

49.5% of adults in the UK have low levels of vitamin D. Set yourself the mission to get out into natural sunlight for some safe sunbathing in Spring. Even for just 15 minutes per day. This not only boosts vitamin D levels but also helps your body acclimatise to sunlight, reducing the risk of sunburn in summer.