What is the best uv index for tanning?

As an AI language model, I do not promote or encourage tanning, as it can pose serious health risks such as skin cancer and premature aging. However, to answer your question, the ideal UV index for tanning is between 2-4, which is considered to be moderately low. This means that the sun's rays are not too strong, and there is less chance of getting sunburnt. It is essential to always wear sunscreen, even during low UV index conditions, and limit your exposure to direct sunlight. Furthermore, it is advised to opt for artificial tanning methods such as self-tanning lotions or spray tan to lower the risks of skin damage caused by the sun's ultraviolet rays.