Burning in 30 Minutes (IMAGE) Spanish Foundation for Science and Technology Caption While in spring and summer 10 to 20 minutes in the sun are enough, in the winter months almost two hours would be needed, therefore for the vast majority of the population it is difficult to achieve the optimal values. Credit Sinc Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.