Updated Wed 05:23 (Pacific/Honolulu)
USA · Forecast updated Sep 23, 2026, 05:23 UTC
Current Sea Temperature
29.1°C
84.4°F
Very warm water
Valid Sep 23, 2026, 05:23 (Pacific/Honolulu). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
1.7°C above
The typical September average is 27.4°C (81.3°F) from the historical baseline.
Recent trend
Holding fairly steady
Seven-day average: 28.8°C, versus 28.5°C in the prior seven days.
What to wear
Very warm water
Swimwear is usually enough; a rash guard adds sun protection.
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 Kealakekua Bay, typical monthly averages range from about 25.2°C (77.4°F) in February to 27.4°C (81.3°F) in September.
Over the past 30 days, the average sea temperature in Kealakekua Bay has been 28.6°C.
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Kealakekua Bay, calculated from hourly observations for 2023–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 25.3–25.8°C | 25.5°C / 77.9°F |
| February | 25.1–25.4°C | 25.2°C / 77.4°F |
| March | 25.1–25.7°C | 25.3°C / 77.5°F |
| April | 25.1–26.1°C | 25.6°C / 78.1°F |
| May | 25.8–26.4°C | 26.1°C / 79.0°F |
| June | 26.4–26.7°C | 26.6°C / 79.9°F |
| July | 26.7–27.0°C | 26.9°C / 80.4°F |
| August | 27.0–27.3°C | 27.2°C / 81.0°F |
| September | 27.2–27.5°C | 27.4°C / 81.3°F |
| October | 27.1–27.2°C | 27.2°C / 81.0°F |
| November | 26.5–27.1°C | 26.8°C / 80.2°F |
| December | 26.0–26.4°C | 26.3°C / 79.3°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (19.46, -155.96). 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 Kealakekua Bay is 25.5°C (77.9°F), with yearly monthly means from 25.3–25.8°C.
Typical February water temperature near Kealakekua Bay is 25.2°C (77.4°F), with yearly monthly means from 25.1–25.4°C.
Typical March water temperature near Kealakekua Bay is 25.3°C (77.5°F), with yearly monthly means from 25.1–25.7°C.
Typical April water temperature near Kealakekua Bay is 25.6°C (78.1°F), with yearly monthly means from 25.1–26.1°C.
Typical May water temperature near Kealakekua Bay is 26.1°C (79.0°F), with yearly monthly means from 25.8–26.4°C.
Typical June water temperature near Kealakekua Bay is 26.6°C (79.9°F), with yearly monthly means from 26.4–26.7°C.
Typical July water temperature near Kealakekua Bay is 26.9°C (80.4°F), with yearly monthly means from 26.7–27.0°C.
Typical August water temperature near Kealakekua Bay is 27.2°C (81.0°F), with yearly monthly means from 27.0–27.3°C.
Typical September water temperature near Kealakekua Bay is 27.4°C (81.3°F), with yearly monthly means from 27.2–27.5°C.
Typical October water temperature near Kealakekua Bay is 27.2°C (81.0°F), with yearly monthly means from 27.1–27.2°C.
Typical November water temperature near Kealakekua Bay is 26.8°C (80.2°F), with yearly monthly means from 26.5–27.1°C.
Typical December water temperature near Kealakekua Bay is 26.3°C (79.3°F), with yearly monthly means from 26.0–26.4°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 | 26.6°C / 79.9°F | 27.4°C / 81.3°F | 28.4°C / 83.1°F |
| July | 26.9°C / 80.4°F | 27.9°C / 82.2°F | 28.9°C / 84.0°F |
| August | 27.1°C / 80.8°F | 28.1°C / 82.6°F | 29.3°C / 84.7°F |
| September | 27.7°C / 81.9°F | 28.6°C / 83.4°F | 29.5°C / 85.1°F |
Partial coverage: 4 calendar months with records. Profile calculated from 2750 hourly forecast records across 4 monthly periods. This is a growing archive, not a long-term climate normal.
A marine sanctuary on the Big Island's Kona coast, Kealakekua Bay has some of Hawaii's healthiest coral and clearest water. The bay is most protected and snorkel-ready on calm, low-wind mornings.
The current sea surface temperature near Kealakekua Bay is 29.1°C (84.4°F). Over the last 30 days, the average has been 28.6°C.
The water is typically warmest in September, at around 27.4°C (81.3°F) in the 2023–2025 historical baseline.
The water is typically coldest in February, at around 25.2°C (77.4°F) in the same historical baseline.
At 29.1°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 Kealakekua Bay.
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