Cook Islands — Sea Water Temperature and Annual Ranges
Up-to-date sea water temperatures for the coasts of Cook Islands. Learn about today’s conditions, monthly averages, and how the surrounding seas and oceans vary by season. We find every place where you can swim and show you the water temperature there today and throughout the year.
Sea Water Temperature Along the Coast
Chart of Average Temperature Changes Over the Last 60 Days
Places with the Warmest Sea Water Today
The Most Popular Seaside Places
Coastal Seas and Oceans
Water Temperature and Swimming Overview
Regions and Map
Water Temperature Trends
The Cook Islands enjoy warm, tropical seas year-round, with coastal water temperatures typically ranging from about 24 to 29 °C (75 to 84 °F). The warmest months are generally December through March, when seas sit around 28–29 °C (82–84 °F), while the coolest period is usually June through September, with temperatures nearer 24–25 °C (75–77 °F). Because the nation is made up of atolls and volcanic islands with wide, shallow lagoons and surrounding reefs, water temperatures are fairly uniform close to shore, offering pleasant swimming even in the cooler months.
Swimming Conditions
Swimming is widely permitted and popular across the Cook Islands, particularly in protected lagoons where calm waters and good visibility make snorkeling, reef walking, and family swimming safe and enjoyable. Caution is advised in reef passes and on exposed coasts where currents and surf can be strong; local signage, guides, and lifeguards should be heeded. The cyclone season from roughly November to April can bring rough seas, heavy surf, and reduced safety, so beach closures are sometimes necessary during storms. Overall, the combination of warm sea temperatures and sheltered lagoon environments means that coastal swimming is a year-round activity for visitors and residents, provided one follows local guidance and watches for seasonal weather-related hazards.