Can you get vitamin D from the sun after 4pm?

Yes, you can still get vitamin D from the sun after 4 p.m., but the effectiveness of sunlight in producing vitamin D decreases as the sun gets lower in the sky, particularly as it moves towards sunset. The amount of vitamin D your skin produces from sunlight depends on several factors:

1. Angle of the Sun (UVB Rays)

• UVB rays, which are responsible for triggering the production of vitamin D in the skin, are more intense when the sun is higher in the sky (typically between 10 a.m. and 4 p.m.). However, even after 4 p.m., UVB rays can still be effective, but their intensity is reduced as the sun begins to set.
• After 4 p.m., especially in areas with higher latitudes (farther from the equator), the sun is lower in the sky, and UVB rays are weaker. In these conditions, it may not be as effective to get enough UVB exposure to produce adequate amounts of vitamin D.

2. Time of Year

• The time of year plays a significant role in how much UVB exposure you can get. During the winter months, even midday sun might not have enough intensity to trigger vitamin D production in certain regions, especially at higher latitudes.
  • In contrast, during summer months, especially in tropical or subtropical regions, afternoon sun (after 4 p.m.) may still provide sufficient UVB rays to produce vitamin D, but the amount will depend on how much time you're exposed to the sun.

3. Latitude and Altitude

• People living closer to the equator (lower latitudes) or at higher altitudes may get effective UVB exposure for a longer part of the day, including after 4 p.m.
  • In contrast, people at higher latitudes (e.g., northern or southern regions) experience weaker UVB rays, especially during the winter months. In such locations, vitamin D production from the sun is often limited to midday hours.

4. Skin Type

• Individuals with darker skin may need longer exposure to sunlight to produce the same amount of vitamin D compared to individuals with lighter skin because darker skin has more melanin, which reduces the skin's ability to produce vitamin D. Therefore, even after 4 p.m., people with darker skin may need longer exposure to produce adequate vitamin D.

5. Duration of Sun Exposure

• The longer you are in the sun, the more vitamin D you can produce. Even if the sun is lower in the sky, if you stay outside long enough (e.g., 30 minutes to an hour), you can still get a good amount of vitamin D from the sunlight.
  • However, it’s important to balance this with the risk of skin damage and skin cancer from prolonged sun exposure.

6. Environmental Factors

• Cloud cover, pollution, and even the time of day can affect how much UVB radiation reaches your skin. If you're in an area with high pollution or heavy cloud cover, your ability to synthesize vitamin D will be reduced, even if it's afternoon.

Conclusion: Can You Get Vitamin D After 4 p.m.?

• Yes, you can still get vitamin D after 4 p.m., but the amount you produce will be lower compared to midday hours when the sun is higher in the sky and UVB rays are more intense.
• To maximize vitamin D production:
  • Aim for sun exposure during midday hours (10 a.m. to 3 p.m.), when UVB rays are most potent.
  • If you're in the sun after 4 p.m., it’s still possible to get some vitamin D, especially if you stay outside for a longer period.
  • Be mindful of the season, latitude, and skin type when determining how much sun exposure you need for adequate vitamin D synthesis.

If you're concerned about vitamin D deficiency, it’s also important to supplement your intake with foods rich in vitamin D (e.g., fatty fish, fortified dairy, egg yolks) or take supplements, especially during months when sun exposure is limited.