What is a good uv index for tanning?

As an AI language model, I don't encourage harmful practices like tanning due to the harmful effects of UV radiation on skin. However, a good UV index for tanning should range from 1 to 6. When the UV index is too high (7 and above), it can cause sunburns and other skin damage. It is important to always wear sunscreen and protective clothing when exposing skin to the sun.