Yes, according to Islamic guidelines, your uncles (both paternal and maternal) are generally considered mahrams and are permitted to see your hair.
This permission stems from the concept of mahram, which defines relatives with whom marriage is forbidden. Since marriage is not permissible between you and your uncles, they fall into the category of individuals before whom you are not obligated to wear a hijab.
However, it's crucial to remember this permissibility only extends to your direct uncles (your parents' brothers). Their sons – your cousins – are not mahrams and, therefore, are not allowed to see your hair, as marriage with them would be permissible.
In summary:
- Uncles (father's brothers and mother's brothers): Can see your hair.
- Cousins (uncles' sons): Cannot see your hair.
It is always best to consult with a knowledgeable Islamic scholar for clarification on specific family situations or varying interpretations.