Alta Lake is the longest of Whistler's five lakes, stretching about 4.5 kilometres through the valley floor. It's less busy than the areas immediately around the village and is popular for windsurfing, paddling, swimming, and quiet picnicking along its shores. The Valley Trail runs along the western edge, making it accessible by bike or on foot from the village.
Rainbow Park on the northwest shore is the main swimming and beach area, with a dock, grassy areas for lounging, and good mountain views. The lake is fed by snowmelt and can be cool well into summer, but by August the shallower sections near the beach warm up considerably. This is where locals come to escape the crowds in the village core.