Joshua Tree is open every day of the year. Oasis and Joshua Tree Visitor Centers are open all year from 8am to 5pm and Cottonwood Visitor Center is open all year from 9am to 3pm. Black Rock Nature Center is open daily from October to May, 8am to 4pm, except on Fridays (noon to 8pm). Unlike most national parks summer is the least popular time to visit, with daytime high temperatures exceeding 100°F. Temperatures gradually subside and by fall the climate is pleasant. During winter daytime highs reach into the 60s°F, but overnight lows are often below freezing. Spring is the best time to visit Joshua Tree. Temperatures are ideal in March and April. And depending on the amount of winter rain, you may have the opportunity to witness a spectacular array of wildflowers in bloom. Joshua Tree is often dry—after all it is a desert—receiving on average 4 inches of precipitation each year.