Zion has a marvelous climate in spring. It's warm and sunny during the day but cools off perfectly in the evening. This is perfect for sleeping but also for having a few beers around camp. You can wear shorts but you'll need your fleece to stay warm. We liked to buy local beers at the grocery store and enjoy them outside. This allows you to enjoy the park and its serenity more but also to sample the local products. One funny one we had was Polygamy Porter. As you can imagine, a popular one in Mormon Utah. Where else would a beer label tout not only "why have just one?" but also "bring some home to the wives!"
Dress Code: Bring out that fleece, you'll need it.
In the evenings, park rangers host programs in the campground ampitheatres. The topics vary, but the lecture programs provide information concerning the park's history, plant and animal life and geology.