When Is the Best Time
It is best in the morning and evening with clouds in the sky. In the late spring, the vegetation behind the hat turns green and this is ideal.
The Mexican Hat is very easy to get to and there are good roads around it so you can get good views from many angles.
This is a nice place to see a very unique rock formation called the Mexican Hat. This area is just north of Monument Valley and only a few minutes drive North.
https://en.wikipedia.org/wiki/Mexican_Hat,_Utah