The water temperature at Jones Beach on Long Island varies significantly by season and is notoriously "refreshing" even in the height of summer. During the peak swimming months of July and August, the Atlantic Ocean typically reaches a range of 20°C to 23°C (68°F to 74°F). While this is comfortable for most active swimmers, it is significantly cooler than the tropical waters of Florida or the Caribbean. In the early season (June), the water is often a bracing 16°C to 18°C (60°F to 65°F), which can be a shock to the system without a wetsuit. By September, the ocean often holds its "thermal mass" and stays quite pleasant for several weeks. In 2026, with the slight rise in coastal temperatures, locals have noted that the "warm water" window has extended slightly longer into the autumn. However, because Jones Beach faces the open Atlantic, it is subject to upwelling, where wind patterns can suddenly pull deep, cold water to the surface, causing the temperature to drop by several degrees in a single afternoon, so it's always wise to "test the waters" before diving in.