Are ocean water temperatures in Hawaii warm enough for year round swimming?

Is the ocean temperature in Hawaii warm enough for swimming and ocean sports? Yes, it is! Even in the colder winter months? Yes, it is!

How do Hawaii ocean temperatures compare month to month?

Referencing data for Honolulu, Oahu from NOAA, ocean temperatures range from 76°F (24.4°C) to 81°F (27.2°C). The following chart shows Honolulu’s monthly water temperature average.

We’ve only referenced Honolulu, Oahu temperatures so far. How do ocean temperatures compare for the other Hawaiian Islands? They’re actually really close. For example, in Kauai, which is the northernmost of the major Hawaiian Islands, ocean temperatures range from 77°F to 83°F. On the beach resort side of Hawaii (Big) Island, ocean temperatures range between 77°F and 81°F.

How do Hawaii ocean temperatures compare to US mainland coastal destinations?

For comparison let’s look at a couple of the warmer US mainland coastal cities from the west and east coasts — San Diego, California and Miami Beach, Florida. In San Diego ocean temperatures vary from a winter low of 59°F to a late summer high of 72°F. So, Hawaii’s ocean temperatures are significantly warmer than San Diego’s throughout the year. In Miami Beach, water temps average as low as 71°F and as high as 86°F. In comparison to Hawaii, Miami’s water temperatures dip lower than Hawaii’s in the winter, but are a bit warmer in the summer. For a look at other coastal temperatures, see this link to the NOAA data.

At what water temperature do you need a thermal wetsuit?

For even more comparison, we wondered at what water temperature is a thermal protected wetsuit recommended? Per the National Center for Cold Water Safety, temperatures below 70°F are considered “dangerous” because most people have difficulty controlling their breathing. As a reminder, Hawaii’s water temperatures stay several degrees above 70°F and are warm enough for swimming and snorkeling.

The National Center for Cold Water Safety also provides some useful water temperature reference points:

85F(29.4C) Water feels pleasantly cool rather than warm.

77-82F(25-28C) Swimming pool temperature range for Olympic competition.

70F(21C) Water feels quite cold to most people. Treat any water temperature below 70F (21C) with caution.

40F(4.4C) or lower Water is painfully cold.

If you plan to scuba dive in Hawaii, you will most likely want/need a wetsuit because the deeper you descend into the water, the cooler the temperatures. If you are diving, inquire with your diving tour/supply company for their advice.

Other ocean temperature notables:

• The ocean or pool will feel colder when you initially get in from being in the warm sun. I’ve noticed this when I dive in to snorkel. I’ve found that I need 30 seconds or so to adjust to the change from the warm air temperature to the cooler water temperature. Sometimes, I just have to catch and calm my breathing.
• When snorkeling in Hawaii, you may encounter small patches of distorted views and colder water. Those are fresh water springs in the ocean.