Zion National Park is one of my favorite places. The colors, the hikes and the scenery are breathtaking. I went during fall for the fall colors. It's a great time to go because they stop the buses entering the park and you can drive in and explore on your own time. I believe they still force you to take the bus into the park during summer hours but I'm not 100%. As a photographer, it's better when you get to come and go when you please, utilizing that early morning or late evening light.
Below is an early morning shot of the Court of the Patriarchs. Just as the sun was coming up and the moon was going down.