Hanauma Bay — Sea temperature now
Volcanic crater snorkel preserve.
Very warm water with a light chop and a light breeze — great swimming conditions.
Location
Hanauma Bay on the map, with nearby beaches and live sea temperatures.
7-day forecast
Water, air, waves, wind and UV outlook for the week ahead.
Monthly sea temperature averages
Typical year-round water temperature, based on regional climatology.
Best time to swim in Hanauma Bay
The sea in Hanauma Bay peaks in July, when the water averages around 28°C.
The main swimming season runs from April – November, when surface temperatures stay comfortable for extended sessions.
On average, 8 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
Shoulder months like March and December are noticeably cooler but often quieter, with fewer crowds and steadier weather.
The coldest month is typically January at around 18°C, when cold-water swimmers dominate the coast.
Hanauma Bay sea temperature history
Long-term climatology for Hanauma Bay shows an annual mean sea temperature of 23°C, ranging from 18°C in winter to 28°C at the summer peak.
The seasonal swing is roughly 10°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.
Recent decades have trended slightly warmer at Hanauma Bay, in line with regional sea-surface temperature records for the wider basin.
Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.
Hanauma Bay sea temperature: frequently asked questions
What is the warmest month to swim in Hanauma Bay?
July is the warmest month in Hanauma Bay, when the sea averages about 28°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Hanauma Bay?
The coldest month in Hanauma Bay is typically January, when the water averages around 18°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Hanauma Bay without a wetsuit?
The main swimming season in Hanauma Bay runs from April – November — about 8 months a year when the sea sits above 20°C, the level most swimmers describe as pleasant without a wetsuit.
Do I need a wetsuit in Hanauma Bay?
Outside peak summer the water in Hanauma Bay drops toward 19°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable. In peak months most swimmers go without.
What is the average sea temperature in Hanauma Bay?
The long-term annual mean sea temperature in Hanauma Bay is about 23°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Hanauma Bay?
The live reading at the top of this page shows the current sea temperature in Hanauma Bay, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
Year-round sea temperature
Best swim months: Apr – May – Jun – Jul – Aug – Sep – Oct – Nov
| Month | Sea | Comfort |
|---|---|---|
| Jan | 18°C | Pleasant |
| Feb | 18°C | Pleasant |
| Mar | 19°C | Pleasant |
| Apr | 21°C | Pleasant |
| May | 23°C | Warm |
| Jun | 26°C | Hot |
| Jul ⭐ | 28°C | Hot |
| Aug | 28°C | Hot |
| Sep | 27°C | Hot |
| Oct | 25°C | Warm |
| Nov | 22°C | Warm |
| Dec | 19°C | Pleasant |