When to Go

Most of the park's one million annual visitors still come between late fall and early spring, taking advantage of moderate temperatures and the lack of rainfall. During these cooler months you will need to book a room in advance, but don't worry: the park never feels crowded. If you visit during summer, believe everything you've ever heard about desert heat—it can be brutal, with temperatures often topping 120°F. The dry air wicks moisture from the body without causing a sweat, so drink plenty of water. Bring sunglasses, a hat, and sufficient clothing to block the sun's rays and the wind. Flash floods are common; sections of roadway can be flooded or washed away. The wettest month is February, when the park receives an average of 0.3 inch of rain.