Oahu water temperature
The sea off Oahu is warmest in September, around 80°F (27°C), and coolest in March, around 75°F (24°C).
Photo: Ossewa, CC BY-SA 4.0
Sea temperature by month
| Month | Sea | Feels | Air high |
|---|---|---|---|
| January | 76°F (24°C) | Pleasant | 80°F |
| February | 75°F (24°C) | Pleasant | 80°F |
| March | 75°F (24°C) | Pleasant | 81°F |
| April | 76°F (24°C) | Pleasant | 83°F |
| May | 77°F (25°C) | Warm | 85°F |
| June | 78°F (26°C) | Warm | 87°F |
| July | 79°F (26°C) | Warm | 88°F |
| August | 80°F (27°C) | Warm | 89°F |
| September | 80°F (27°C) | Warm | 88°F |
| October | 80°F (27°C) | Warm | 87°F |
| November | 79°F (26°C) | Warm | 84°F |
| December | 77°F (25°C) | Warm | 82°F |
Average sea-surface temperature just offshore, 1991–2020. Water in shallow bays runs a little warmer on sunny afternoons.
On the water in Oahu
Questions
When is the water warmest in Oahu?
September, at about 80°F (27°C).
Can you swim in Oahu all year?
Yes. The sea stays at 75°F or warmer even in March.
Do I need a wetsuit to snorkel in Oahu?
In March, at 75°F, a 3 mm wetsuit makes a long snorkel much more comfortable. Many tours include or rent one.
