How long should I get vitamin D from the sun?

December 29, 2025 •

4 min read

According to Healthline, an estimated 35% of American adults and 50% of the world's population have a vitamin D deficiency, making sun exposure a crucial topic for public health [1]. But exactly how long should I get vitamin D from the sun? The answer varies, depending on several factors including skin type, geographic location, and the time of year [1].

Quick Summary

The duration of sun exposure for adequate vitamin D production varies significantly. Time of day, skin color, and location are key factors that influence the required exposure. A brief, strategic period of midday sun can be highly effective and safe for many people, especially when combined with careful monitoring.

Key Points

Midday Sun is Best: The peak time for effective vitamin D synthesis is between 10 a.m. and 4 p.m., when UVB rays are most intense [1].
Skin Color Matters: Lighter-skinned individuals need less time in the sun (10-15 minutes) than those with darker skin (25-40 minutes) to produce the same amount of vitamin D [1].
Geography and Season Impact Exposure: Latitude and time of year affect UV intensity; people at higher latitudes or in winter need more sun or an alternative source [1, 2].
Strategic, Unprotected Exposure is Key: For short intervals, bare skin is needed, but for prolonged exposure, sunscreen is vital to prevent skin damage and cancer [1].
Combine with Other Sources: Sunlight is not always enough, especially during winter months, and should be supplemented with vitamin D-rich foods or oral supplements [1].
The Body Regulates Itself: Your body produces a limited amount of vitamin D from sun exposure, making toxicity from sunlight alone unlikely [1].
Avoid Sunburn: Your goal is to get vitamin D, not to burn your skin. Sunburn increases skin cancer risk and does not increase vitamin D production [1].

Determining Your Optimal Sun Exposure Time

Your body produces vitamin D when your bare skin is exposed to sunlight's ultraviolet B (UVB) rays [1]. However, a one-size-fits-all recommendation for sun exposure is impossible due to the many variables at play. The right amount of time depends on your unique circumstances. Several key elements dictate how much sun you need for vitamin D synthesis [1].

Factors Influencing Vitamin D Synthesis

Time of Day: The midday sun, typically between 10 a.m. and 4 p.m., offers the most intense and effective UVB radiation [1]. During these peak hours, less time is needed to produce sufficient vitamin D. Exposure during early morning or late afternoon yields significantly less, even on sunny days [2].
Skin Pigmentation: The amount of melanin in your skin, which dictates its color, acts as a natural sunscreen [1]. People with darker skin tones have more melanin, which protects against sunburn but also reduces the rate of vitamin D production. Consequently, they require longer exposure to synthesize the same amount of vitamin D as a person with lighter skin [1].
Geographic Location: Latitude plays a critical role. The closer you are to the equator, the more direct the sun's rays are, and the more effective UVB radiation is for vitamin D production [1]. Conversely, people at higher latitudes often struggle to produce enough vitamin D during winter months, and may need supplements, as the sun's angle and UV intensity are insufficient [1, 2].
Season: In line with geographic location, the season has a major impact. In winter, even in sunny regions, the sun's angle is lower, and UVB rays are weaker. Studies show that people in many northern regions can produce little to no vitamin D from sunlight between November and February [1].
Amount of Skin Exposed: The more skin you expose, the faster you can produce vitamin D [1]. Exposing your face, arms, and legs for a short period is more effective than just exposing your hands. Some experts suggest exposing about a third of your skin's total area [1].
Sunscreen Use: Sunscreen is designed to block harmful UV rays, and this includes UVB rays necessary for vitamin D production [1]. While prolonged, unprotected exposure should be avoided due to skin cancer risks, some studies suggest that in real-world scenarios, people don't apply sunscreen perfectly, allowing some vitamin D synthesis to occur [1].

Safe Sun Exposure: A Balanced Approach

Finding the right balance between producing vitamin D and protecting your skin from UV damage is key. Excessive sun exposure can lead to sunburn, premature aging, and increase the risk of skin cancer [1]. The recommendation is to aim for brief, unprotected sun exposure, and then cover up or apply sunscreen if staying out longer [1].

Sun Exposure Recommendations by Skin Type and Season

This table provides a general guideline for midday sun exposure for fair-skinned and dark-skinned individuals in temperate climates. These are estimates and should be adjusted based on personal sensitivity and local conditions [1, 2].


Skin Type	Summer	Spring/Autumn	Winter
Fair Skin	10-15 minutes [1]	15-20 minutes [2]	30 minutes or more, often inadequate [2]
Dark Skin	25-40 minutes [1]	60 minutes [2]	90 minutes or more, often inadequate [2]

Practical Tips for Daily Sunshine

Timing is Everything: Maximize your sun exposure efficiency by stepping out around midday, when UVB rays are strongest. This is especially important in winter when sunlight is weaker [1].
Expose Strategically: Focus on exposing arms, legs, and your back to maximize the skin surface area for production [1]. Remember to protect your face and eyes with a hat and sunglasses [1].
Use Sunscreen Wisely: For short, targeted sun sessions for vitamin D, skip the sunscreen. For any longer periods of sun exposure, apply sunscreen with an SPF of 15 or higher to prevent skin damage [1].
Embrace Cloudy Days: Don't be deterred by clouds. While they reduce UV intensity, some UVB rays can still get through, allowing for some vitamin D synthesis, though it may take a bit longer [3].
Consider Other Sources: Especially during winter or for those at higher latitudes, relying solely on sunlight for vitamin D is insufficient [1]. Incorporate fatty fish, fortified foods, and supplements into your diet to ensure adequate intake [1].

Outbound Link

For a deeper dive into the health implications of vitamin D and potential deficiencies, consult the Health Professional Fact Sheet on Vitamin D from the NIH Office of Dietary Supplements.

Conclusion

Understanding how to safely and effectively get vitamin D from the sun is a nuanced process that balances the need for this essential nutrient with the risks of UV exposure. While a few minutes of midday sun exposure several times a week is effective for many, personal factors like skin color and geographic location necessitate a personalized approach. For those in northern latitudes or with darker skin tones, relying solely on sunlight is often not enough, particularly in winter. By combining strategic, brief sun exposure with dietary sources and supplements, you can maintain healthy vitamin D levels year-round while minimizing skin damage. Always listen to your body and prioritize safety by avoiding sunburn at all costs.

Frequently Asked Questions

For many, 5 to 30 minutes of unprotected midday sun exposure several times per week on the face, arms, and legs is enough for sufficient vitamin D synthesis [2]. However, this varies based on skin type, location, and season [1].

No, the glass in windows blocks the sun's UVB rays, which are the specific type of radiation needed for your skin to produce vitamin D. You must expose bare skin directly to the sun for synthesis to occur [1].

Sunscreen, by design, blocks the UVB rays necessary for vitamin D production [1]. However, since most people don't apply enough sunscreen or reapply it frequently, some vitamin D synthesis can still occur even while wearing it [1].

No, you cannot get too much vitamin D from the sun alone. Your body has a self-regulating mechanism that limits the amount it produces, making vitamin D toxicity from sunlight improbable [1].

Yes, people with darker skin have more melanin, which provides more natural sun protection but also slows vitamin D synthesis. They require more time in the sun to produce the same amount of vitamin D as a person with lighter skin [1].

The best time is around midday, typically between 10 a.m. and 4 p.m., when the sun's UVB rays are at their most intense. This allows for shorter, more effective exposure sessions [1].

Symptoms of vitamin D deficiency can include fatigue, bone pain, muscle weakness, frequent infections, back pain, and a depressed mood [3]. A blood test is the most accurate way to confirm low levels [1].

In many northern latitudes, the sun's rays are too weak in the winter to produce sufficient vitamin D. While some exposure is beneficial, it's often necessary to rely on diet and supplements during these months [1, 2].