Water & Weather · Oahu
Waikiki Water Temperature, Month by Month
The ocean at Waikiki runs between 73.9 and 85.6 degrees Fahrenheit and averages 79. In 76,243 hourly readings it has never once been cold enough to want a wetsuit. Here is what it actually measures, month by month.
Waikiki water temperature right now
85°F
Above the September average of 81.6°F.
NOAA CO-OPS station 1612340, Honolulu Harbour, about 5.5 km west of Waikiki.
Waikiki water sits in a narrow band all year. The coolest month, February, averages 76.8°F. The warmest, September, averages 81.6°F. That is a spread of 4.8 degrees across an entire year, which is narrower than most visitors expect and is the single most useful thing to know before you pack.
What it means in practice: bring a rashguard for the sun, not for warmth. Nobody at Waikiki owns a wetsuit. The season that actually changes your day here is the swell season, not the temperature, and the Waikiki surf guide covers which months bring the south swell that wakes the reefs up.
Waikiki water temperature by month
Average is the mean of every hourly reading in that month. Typical range is the band the water sits in nine times out of ten, which is more useful for packing than the records beside it. Records are the single coldest and warmest readings in 9 years.
| Month | Average | Typical range | Record low | Record high |
|---|---|---|---|---|
| January | 77°F | 76 to 79°F | 74.8°F | 81.0°F |
| February | 77°F | 76 to 78°F | 74.8°F | 80.6°F |
| March | 77°F | 76 to 79°F | 73.9°F | 80.6°F |
| April | 78°F | 76 to 80°F | 75.6°F | 81.5°F |
| May | 79°F | 77 to 80°F | 76.6°F | 82.4°F |
| June | 80°F | 79 to 81°F | 77.5°F | 84.0°F |
| July | 81°F | 79 to 82°F | 77.9°F | 84.7°F |
| August | 81°F | 80 to 84°F | 78.6°F | 85.1°F |
| September | 82°F | 80 to 83°F | 79.0°F | 85.6°F |
| October | 81°F | 80 to 83°F | 78.4°F | 83.8°F |
| November | 80°F | 78 to 81°F | 77.2°F | 82.4°F |
| December | 78°F | 76 to 80°F | 74.3°F | 81.9°F |
Computed from 76,243 hourly readings at NOAA CO-OPS station 1612340, 2016 to 2026.
What to wear in the water at Waikiki
No wetsuit, in any month. The coldest reading in the entire record is 73.9°F, in March, and a single reading at that is an outlier rather than a day you should plan around. Even February, the coolest month, averages 76.8°F.
A rashguard, for the sun. Twenty-one degrees north of the equator, the thing that ends a swim early is sunburn across your back, not cold. A long sleeve rashguard is worth more than any sunscreen reapplication schedule you will actually keep to.
A 1mm top, only if you are in for hours. A two-hour snorkel or a long lesson in February or March is the one case where a thin neoprene top earns its space in a bag. Children and very lean adults lose heat faster and feel it first. This is a comfort call, not a safety one.
The warmest and coolest months
August, September and October sit within a tenth of a degree of each other at the top of the range, so the warm window is a season rather than a month. September is nominally the warmest at 81.6°F, and the highest reading ever taken is 85.6°F in September.
The bottom of the range is February at 76.8°F, with January and March within a degree of it. Those are also the quietest months for south swell, which makes them the better months for flat-water swimming and snorkelling at Waikiki even though the water is at its coolest. If you are picking a beach around that, the best beaches on Oahu sorts them by what each one is actually good for.
Where these numbers come from
Every figure on this page is computed from NOAA CO-OPS station 1612340, which measures sea water temperature every hour and publishes it. We pulled its full record for 2016 to 2026 and kept 76,243 readings after discarding sensor faults and sentinel values.
That is 9 years of record rather than 11 years of calendar. The sensor was down for almost all of 2018 and 2019, so those years contribute almost nothing and are excluded from the count above rather than quietly averaged in. 2026 runs to date rather than to December, which is also why the records below include this year’s.
One caveat worth stating plainly: station 1612340 sits in Honolulu Harbour, about 5.5 km west of Waikiki and inside a harbour rather than on the open shoreline. Harbour water runs slightly warmer, so expect the water off Kuhio Beach to read around a degree cooler than the table above. It is the nearest station that measures water temperature continuously, and the alternative is reprinting a table with no source attached to it.
Common questions
Is the water in Waikiki warm enough to swim in January?
Yes. January averages 77.5°F and the coldest January reading in 9 years of hourly measurement is 74.8°F. It is the quietest month for south swell, which makes it one of the better months for flat-water swimming at Waikiki.
Do I need a wetsuit in Waikiki?
No. The ocean at Waikiki has never been recorded below 73.9°F in this dataset. Bring a rashguard for the sun rather than for warmth. If you are going to be in the water for two hours or more in February or March, a 1mm top makes a long session more comfortable, and that is a comfort decision rather than a safety one.
When is the water warmest in Waikiki?
September, at an average of 81.6°F. August and October sit within a tenth of a degree of it, so the warm-water window is really August through October rather than one month.
How cold does the water get in Waikiki?
February is the coolest month, averaging 76.8°F. The single lowest reading in the record is 73.9°F, measured in March. The warmest is 85.6°F in September.
How much does Waikiki water temperature change through the year?
4.8 degrees between the coolest month and the warmest. That is a narrower range than most visitors expect, and it is the reason the season that matters at Waikiki is the swell season rather than the water temperature.
Getting in the water
Warm water year round is the reason snorkelling works at Waikiki in any month. Before you swim anywhere on the island, it is worth checking whether it is safe to swim today, which covers surf height, current advisories and beach closures.
Waikiki 2 hour Turtle Canyon Snorkeling Adventure
Turtle Canyon sits just off Waikiki, which keeps the boat ride short and the water flat. Two hours, gear included, and the water is in the high seventies or low eighties whichever month you go.
We may earn a commission if you book through this link, at no extra cost to you.
More Oahu guides
- The Waikiki Surf Guide, for which reef suits your level and what the swell is doing right now.
- Is it safe to swim in Oahu today, for surf height, current advisories and beach closures before you get in.
- The best beaches on Oahu, for where to swim, where to snorkel, and where to find shade.
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