Overview Download the NPS app prior to visiting the park β trail maps and more! Cottonwood Campground is one of the best places in Joshua Tree National Park for stargazing and wildflower viewing. Easy access from Interstate 10, makes it a popular stopover for travelers. To get the most out of your visit Plan Like a Park RangerΒ Visitors who enjoy warm, dry winters flock to Joshua Tree from October through May, when temperatures reach between 70 to 90-degrees during the day and drop to 40 to 60-