Cloudy Skies, Less Sunlight: Can Monsoon Affect Your Vitamin D Levels?

Grey skies, drizzle and a good reason to stay in. The monsoon is cosy, but it can quietly affect something your body makes from sunlight: vitamin D.

Sunshine, then clouds

Your skin makes vitamin D when UVB rays from the sun reach it. In a study in Lucknow, cloud cover during the rainy season was linked to lower UVB energy at the surface. Another health-sector source notes that monsoon clouds sharply cut UV penetration, which makes vitamin D synthesis harder.

Monsoon is not the worst season for this, though. In the same Lucknow study, midday UVB readings were lowest in winter (November to January) and highest in May and June. The rainy months are a dip in the middle, not the bottom.

The bigger problem: we were low already

India is a sunny country, yet deficiency is widespread. Studies report that 75 to 90 percent of the population is deficient across age groups, in both north and south, and in both urban and rural areas. The reasons researchers give include little skin exposed to the sun, skin pigmentation, low dietary calcium and possibly air pollution. Darker skin needs more sun exposure to make the same amount of vitamin D.

The monsoon adds to this. We spend more time indoors when it rains, and work-from-home routines have cut daily time outdoors further.

Why it matters

Vitamin D is crucial for calcium absorption, which is why it matters for bones. Deficiency often goes undiagnosed because the symptoms can be subtle. They can include body aches, muscle weakness, cramps, slow wound healing and tiredness. These are easy to blame on the weather or a busy schedule.

Simple steps for the rainy season

• Use the sunny breaks. One source suggests sun exposure between 10 AM and 3 PM is best for synthesis. Even 15 to 20 minutes outdoors with arms and legs exposed on a bright day is a reasonable aim.
• Move outside when you can, such as a short walk or a balcony break, rather than staying indoors all day.
• Include vitamin D foods such as eggs, fatty fish and fortified products. Food alone rarely closes the gap.
• Get tested if you have persistent aches, weakness or fatigue, or if you are pregnant, older or mostly indoors.
• Take supplements only on medical advice. They can help people at high risk, but the right dose depends on your blood levels.

The monsoon alone won't cause deficiency, but it can push borderline levels lower. A few sunny minutes a day and a simple blood test can keep your bones and muscles on track.