Northern Mariana Islands — Sea Water Temperature and Annual Ranges
Up-to-date sea water temperatures for the coasts of Northern Mariana 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 Northern Mariana Islands, a chain of volcanic and limestone islands in the western Pacific, enjoys warm tropical seas year-round. Sea surface temperatures typically range from about 25–27 °C (77–81 °F) in the coolest months of December through February to roughly 28–30 °C (82–86 °F) during the warmer, wetter season from May to October. Transitional months such as March–April and September–November often see temperatures in the mid-to-high 20s °C (around 78–84 °F). These consistently mild water temperatures make the coastal waters pleasant for recreational use throughout the year, with modest seasonal variation rather than extreme swings.
Swimming Conditions
Swimming is generally permitted and popular across accessible beaches and protected bays because the water is warm and inviting most months. Many visitors and residents swim, snorkel, and dive; conditions are typically calmest and visibility best during the dry season (roughly November to April). However, local authorities may close beaches or advise against entering the water during typhoons, heavy rains, strong trade winds, or when hazardous currents and surf are present. There can also be occasional jellyfish or other stingers, and coral and marine habitats should be respected to avoid injury and environmental damage. Lifeguard coverage is limited in many areas, so swimmers should heed posted warnings, consult local guidance, and exercise normal ocean safety precautions. Overall, the Northern Mariana Islands offer very good year-round swimming opportunities, with the safest and clearest conditions often found in the drier months.