Perhaps nowhere else in the U.S. are freshwater swimming holes more desired than in Southern California, and for good reason. Almost all of SoCal is desert, and during the long inland months of summer, daytime heat can easily rise to 115 degrees.
Luckily, the mountains of SoCal rise high (San Gorgonio Mountain in the San Bernardinos peaks out at an impressive 11,503 feet) and capture a surprisingly plentiful bounty of snow in the winter months that saturate the ground and create pools, springs, and waterfalls in the most unexpected places. That being said, California is no stranger to drought, and it is still composed of arid landscapes that will dry up fast by as early as early-July, so catching the right swimming hole certainly favors the early birds. And you can count on most of them being nearly dry by end of August and nonexistent by September.
Before heading out, though, remember that these swimming holes are sacred to many and proper etiquette and ethical behavior are crucial to keeping them open to the public for years to come. Stay safe, be courteous, and have fun!
Swimming holes and cliff jumping can be extremely dangerous and unpredictable outdoor activities that pose significant risks regarding personal safety. Changing water levels, unseen rocks, and river bottoms that have shifted with currents and seasonal weather can turn a well-known jumping area into a serious hazard. Prior to engaging in these activities, extensively scout the current conditions, and understand the risks involved with serious injury and the logistical challenges of evacuation from the water so you can make safe decisions.
The Forest Service and other local management agencies are considering closing access to many of these sensitive locations due to excessive trampling of plants, large amounts of garbage, cans and glass bottles, graffiti, human waste, and toilet paper left behind. They simply do not have the staff or the funding to attend to these issues. If you want to continue enjoying these areas, pack out all garbage and toilet paper and dispose of it properly, use vault toilets and other restroom facilities when provided, and stay on established paths. Using these areas responsibly will increase the chance that people can continue to enjoy them.