INSTRUMENT / SEA TEMPERATURE
Also spelled Kona Coast / Hawaii Island
Updated Wed 13:02 (Pacific/Honolulu)
USA · Forecast updated Nov 11, 2026, 13:02 UTC
Kona and the Big Island's leeward west coast—including Kailua-Kona (Kahaluu Beach Park) and South Kona (Kealakekua Bay, Two Step at Honaunau)—typically have 24-27 °C water year-round. Because the island center is inland, compare the monitored Kona and Kohala beach forecasts for wind, swell and manta or daytime reef conditions.
In the historical baseline for Big Island, typical monthly averages range from about 25.2°C (77.4°F) in February to 27.4°C (81.3°F) in September.
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Average of 2 snorkeling spots around Big Island (Anaehoomalu Bay, Kahaluu Beach Park), from hourly observations for 2023–2025. The island pin is inland, so this uses the beaches. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 25.3–25.8°C | 25.6°C / 78.1°F |
| February | 25.1–25.4°C | 25.2°C / 77.4°F |
| March | 24.9–25.8°C | 25.3°C / 77.5°F |
| April | 25.0–26.2°C | 25.6°C / 78.1°F |
| May | 25.9–26.5°C | 26.2°C / 79.2°F |
| June | 26.4–26.9°C | 26.6°C / 79.9°F |
| July | 26.7–27.1°C | 26.9°C / 80.4°F |
| August | 27.1–27.4°C | 27.3°C / 81.1°F |
| September | 27.1–27.6°C | 27.4°C / 81.3°F |
| October | 27.1–27.4°C | 27.2°C / 81.0°F |
| November | 26.6–27.1°C | 26.8°C / 80.2°F |
| December | 26.0–26.4°C | 26.2°C / 79.2°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Equal-weight mean of those spots' coastal baselines. Each month is the mean of yearly monthly means; the range is the lowest and highest yearly monthly mean across those spots. 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 Kona & Big Island is 25.6°C (78.1°F), with yearly monthly means from 25.3–25.8°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: December 26.2°C · February 25.2°C.
Explore Kona & Big Island sea temperature in January, including swim comfort and month comparisons →
Typical February water temperature near Kona & Big Island is 25.2°C (77.4°F), with yearly monthly means from 25.1–25.4°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: January 25.6°C · March 25.3°C.
Typical March water temperature near Kona & Big Island is 25.3°C (77.5°F), with yearly monthly means from 24.9–25.8°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: February 25.2°C · April 25.6°C.
Explore Kona & Big Island sea temperature in March, including swim comfort and month comparisons →
Typical April water temperature near Kona & Big Island is 25.6°C (78.1°F), with yearly monthly means from 25.0–26.2°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: March 25.3°C · May 26.2°C.
Explore Kona & Big Island sea temperature in April, including swim comfort and month comparisons →
Typical May water temperature near Kona & Big Island is 26.2°C (79.2°F), with yearly monthly means from 25.9–26.5°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: April 25.6°C · June 26.6°C.
Explore Kona & Big Island sea temperature in May, including swim comfort and month comparisons →
Typical June water temperature near Kona & Big Island is 26.6°C (79.9°F), with yearly monthly means from 26.4–26.9°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: May 26.2°C · July 26.9°C.
Explore Kona & Big Island sea temperature in June, including swim comfort and month comparisons →
Typical July water temperature near Kona & Big Island is 26.9°C (80.4°F), with yearly monthly means from 26.7–27.1°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: June 26.6°C · August 27.3°C.
Explore Kona & Big Island sea temperature in July, including swim comfort and month comparisons →
Typical August water temperature near Kona & Big Island is 27.3°C (81.1°F), with yearly monthly means from 27.1–27.4°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: July 26.9°C · September 27.4°C.
Explore Kona & Big Island sea temperature in August, including swim comfort and month comparisons →
Typical September water temperature near Kona & Big Island is 27.4°C (81.3°F), with yearly monthly means from 27.1–27.6°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: August 27.3°C · October 27.2°C.
Typical October water temperature near Kona & Big Island is 27.2°C (81.0°F), with yearly monthly means from 27.1–27.4°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: September 27.4°C · November 26.8°C.
Explore Kona & Big Island sea temperature in October, including swim comfort and month comparisons →
Typical November water temperature near Kona & Big Island is 26.8°C (80.2°F), with yearly monthly means from 26.6–27.1°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: October 27.2°C · December 26.2°C.
Typical December water temperature near Kona & Big Island is 26.2°C (79.2°F), with yearly monthly means from 26.0–26.4°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: November 26.8°C · January 25.6°C.
Big Island snorkel report hub for Kona reefs, protected bays and lava-rock entries.
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.
Prices and availability from Viator. Check conditions before you book.
We may earn a commission at no extra cost to you.
Free cancellation available
Free cancellation available
Free cancellation available
Free cancellation available
Free cancellation available
Free cancellation available
See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Big Island.
View Snorkel Forecast →