USSF and AYSO have modified their recommendations related to the use of referee caps to enhance their support for the health and safety of referees. The detailed information along with some good tips can be found here
If a referee wears a cap, the following requirements apply:
- The cap must not endanger the safety of the official or the players.
- The cap should be solid black or predominately black color.
- The cap may display the logo of AYSO (preferred), USSF, or FIFA, but should not display other logos, slogans, or commercial marks.