Yosemite National Park offers a range of swimming opportunities—from rivers and lakes to our family-friendly pools, which are the only swimming places in Yosemite with lifeguards. River and lake swimming is at-your-own-risk. Life jackets are strongly recommended—especially for children.
Global climate change is impacting Yosemite. Worldwide emissions of greenhouse gases trap heat in the atmosphere, leading to rapid warming observed across the western US. Scientists project that average temperatures in the park may rise by 6.7–10.3°F between 2000 and 2100.
While California's air pollution regulations are among the strictest in the country, topography and geography combine to trap air pollutants in its Central Valley. Westerly winds often blow that pollution into Yosemite, especially during the summer.
Our water is perfectly safe to drink, bath and swim in, but we recommend that you bring bottled water for drinking, due to the fact that our water has a high mineral content.
While true altitude sickness is normally only the concern of mountaineers heading for high summits, you can experience mild symptoms from the elevation in Yosemite—headaches, shortness-of-breath, and the like—as low as 5,000 feet. Staying a step ahead of altitude sickness means taking things slow.