Updated Mon 12:59 (Pacific/Honolulu)
USA · Forecast updated Sep 28, 2026, 12:59 UTC
Current Sea Temperature
26.9°C
80.4°F
Warm water
Valid Sep 28, 2026, 12:59 (Pacific/Honolulu). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
0.4°C below
The typical September average is 27.3°C (81.1°F) from the historical baseline.
Recent trend
Holding fairly steady
Seven-day average: 26.8°C, versus 26.8°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 Kauai, typical monthly averages range from about 24.4°C (75.9°F) in February to 27.5°C (81.5°F) in October.
Over the past 30 days, the average sea temperature in Kauai has been 26.8°C.
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Kauai, calculated from hourly observations for 2023–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 24.4–25.1°C | 24.9°C / 76.8°F |
| February | 24.3–24.5°C | 24.4°C / 75.9°F |
| March | 23.8–25.1°C | 24.4°C / 75.9°F |
| April | 24.3–25.6°C | 24.9°C / 76.8°F |
| May | 25.5–25.7°C | 25.6°C / 78.1°F |
| June | 26.1–26.6°C | 26.3°C / 79.3°F |
| July | 26.4–26.6°C | 26.5°C / 79.7°F |
| August | 26.7–27.3°C | 27.0°C / 80.6°F |
| September | 27.1–27.8°C | 27.3°C / 81.1°F |
| October | 27.2–28.0°C | 27.5°C / 81.5°F |
| November | 26.6–26.8°C | 26.7°C / 80.1°F |
| December | 25.8–26.0°C | 25.9°C / 78.6°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (21.96, -159.71). 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 Kauai is 24.9°C (76.8°F), with yearly monthly means from 24.4–25.1°C.
Typical February water temperature near Kauai is 24.4°C (75.9°F), with yearly monthly means from 24.3–24.5°C.
Typical March water temperature near Kauai is 24.4°C (75.9°F), with yearly monthly means from 23.8–25.1°C.
Typical April water temperature near Kauai is 24.9°C (76.8°F), with yearly monthly means from 24.3–25.6°C.
Typical May water temperature near Kauai is 25.6°C (78.1°F), with yearly monthly means from 25.5–25.7°C.
Typical June water temperature near Kauai is 26.3°C (79.3°F), with yearly monthly means from 26.1–26.6°C.
Typical July water temperature near Kauai is 26.5°C (79.7°F), with yearly monthly means from 26.4–26.6°C.
Typical August water temperature near Kauai is 27.0°C (80.6°F), with yearly monthly means from 26.7–27.3°C.
Typical September water temperature near Kauai is 27.3°C (81.1°F), with yearly monthly means from 27.1–27.8°C.
Typical October water temperature near Kauai is 27.5°C (81.5°F), with yearly monthly means from 27.2–28.0°C.
Typical November water temperature near Kauai is 26.7°C (80.1°F), with yearly monthly means from 26.6–26.8°C.
Typical December water temperature near Kauai is 25.9°C (78.6°F), with yearly monthly means from 25.8–26.0°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 | 25.5°C / 77.9°F | 25.7°C / 78.3°F | 25.9°C / 78.6°F |
| July | 25.5°C / 77.9°F | 26.6°C / 79.9°F | 27.3°C / 81.1°F |
| August | 25.9°C / 78.6°F | 26.9°C / 80.3°F | 27.6°C / 81.7°F |
| September | 26.1°C / 79.0°F | 26.8°C / 80.2°F | 27.7°C / 81.9°F |
| October | 26.6°C / 79.9°F | 26.9°C / 80.4°F | 27.1°C / 80.8°F |
Partial coverage: 5 calendar months with records. Profile calculated from 2281 hourly forecast records across 5 monthly periods. This is a growing archive, not a long-term climate normal.
Kauai snorkel report hub for comparing north-shore summer reefs and south-shore beaches.
The current sea surface temperature near Kauai is 26.9°C (80.4°F). Over the last 30 days, the average has been 26.8°C.
The water is typically warmest in October, at around 27.5°C (81.5°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 26.9°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 Kauai.
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