Updated Tue 10:06 (Pacific/Honolulu)
USA · Forecast updated Sep 22, 2026, 10:06 UTC
Current Sea Temperature
27.3°C
81.1°F
Warm water
Valid Sep 22, 2026, 10:06 (Pacific/Honolulu). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
0.5°C above
The typical September average is 26.8°C (80.2°F) from the historical baseline.
Recent trend
Holding fairly steady
Seven-day average: 27.2°C, versus 27.1°C in the prior seven days.
What to wear
Warm water
Most people are comfortable in swimwear or a light rash guard.
Cold tolerance varies. Wind, session length, sunshine, and exertion also affect comfort; temperature alone does not describe sea conditions or replace the snorkel forecast.
In the historical baseline for Hanauma Bay, typical monthly averages range from about 24.4°C (75.9°F) in February to 26.9°C (80.4°F) in October.
Over the past 30 days, the average sea temperature in Hanauma Bay has been 26.9°C.
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Hanauma Bay, calculated from hourly observations for 2023–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 24.8–25.2°C | 25.1°C / 77.2°F |
| February | 24.4–24.4°C | 24.4°C / 75.9°F |
| March | 24.0–24.7°C | 24.5°C / 76.1°F |
| April | 24.1–25.1°C | 24.8°C / 76.6°F |
| May | 24.8–25.5°C | 25.1°C / 77.2°F |
| June | 25.6–25.8°C | 25.7°C / 78.3°F |
| July | 26.0–26.4°C | 26.2°C / 79.2°F |
| August | 26.4–26.9°C | 26.6°C / 79.9°F |
| September | 26.7–27.0°C | 26.8°C / 80.2°F |
| October | 26.8–27.1°C | 26.9°C / 80.4°F |
| November | 25.6–26.5°C | 26.1°C / 79.0°F |
| December | 25.5–25.7°C | 25.6°C / 78.1°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (21.29, -157.71). Each month is the mean of yearly monthly means; the range is the lowest and highest of those yearly monthly means. Open-Meteo methodology.
Each month uses the 2023–2025 baseline. The range is the lowest and highest yearly monthly mean, not an hourly extreme.
Typical January water temperature near Hanauma Bay is 25.1°C (77.2°F), with yearly monthly means from 24.8–25.2°C.
Typical February water temperature near Hanauma Bay is 24.4°C (75.9°F), with yearly monthly means from 24.4–24.4°C.
Typical March water temperature near Hanauma Bay is 24.5°C (76.1°F), with yearly monthly means from 24.0–24.7°C.
Typical April water temperature near Hanauma Bay is 24.8°C (76.6°F), with yearly monthly means from 24.1–25.1°C.
Typical May water temperature near Hanauma Bay is 25.1°C (77.2°F), with yearly monthly means from 24.8–25.5°C.
Typical June water temperature near Hanauma Bay is 25.7°C (78.3°F), with yearly monthly means from 25.6–25.8°C.
Typical July water temperature near Hanauma Bay is 26.2°C (79.2°F), with yearly monthly means from 26.0–26.4°C.
Typical August water temperature near Hanauma Bay is 26.6°C (79.9°F), with yearly monthly means from 26.4–26.9°C.
Typical September water temperature near Hanauma Bay is 26.8°C (80.2°F), with yearly monthly means from 26.7–27.0°C.
Typical October water temperature near Hanauma Bay is 26.9°C (80.4°F), with yearly monthly means from 26.8–27.1°C.
Typical November water temperature near Hanauma Bay is 26.1°C (79.0°F), with yearly monthly means from 25.6–26.5°C.
Typical December water temperature near Hanauma Bay is 25.6°C (78.1°F), with yearly monthly means from 25.5–25.7°C.
These values come from hourly forecasts SnorkelForecast has stored. They cover only months with records and do not replace the historical baseline.
| Month | Min | Average | Max |
|---|---|---|---|
| June | 25.4°C / 77.7°F | 26.1°C / 79.0°F | 27.4°C / 81.3°F |
| July | 25.9°C / 78.6°F | 26.4°C / 79.6°F | 28.0°C / 82.4°F |
| August | 25.9°C / 78.6°F | 26.7°C / 80.0°F | 27.6°C / 81.7°F |
| September | 26.5°C / 79.7°F | 27.1°C / 80.7°F | 27.7°C / 81.9°F |
Partial coverage: 4 calendar months with records. Profile calculated from 2731 hourly forecast records across 4 monthly periods. This is a growing archive, not a long-term climate normal.
A protected marine life conservation area inside a volcanic cone on Oahu, Hanauma Bay is Hawaii's most popular snorkeling spot. The shallow inner reef stays calm in most conditions; aim for an early slot when water is clearest and crowds are thinnest.
The current sea surface temperature near Hanauma Bay is 27.3°C (81.1°F). Over the last 30 days, the average has been 26.9°C.
The water is typically warmest in October, at around 26.9°C (80.4°F) in the 2023–2025 historical baseline.
The water is typically coldest in February, at around 24.4°C (75.9°F) in the same historical baseline.
At 27.3°C, the water is usually comfortable for swimming and snorkeling.
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See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Hanauma Bay.
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