Oahu and the entire Hawaiian Islands are situated in a tropical semi-humid climate that creates ideal conditions for year-round visitation.

Temperatures are virtually constant throughout the year, with seasons divided into a dry season during the summer (April-October) and a wet season during the winter (October-March). However, it is important to underline that even in the wet season you should not expect long-lasting tropical cyclones, but rather very short intense rains occurring on average once a day, which will not disrupt your holiday in any way.

The great advantage of Oahu's climate is the low probability of temperature extremes. Temperatures are stable throughout the year, so you don't have to worry about extreme heat, much less cold weather.

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The northeastern side of the island is the rainiest, with sporadic rain in the south (Honolulu) and southwest.

Air temperatures and when it rains the most

Fancy a cheap flight to Oahu but not sure if the weather is suitable for the time of year? Check out the detailed breakdown by month of the year.

Weather in January

January is the coldest month on Oahu, but this means average temperatures of around 27°C, and even the evenings or mornings aren't particularly chilly. Rain days average 7 per month, but prolonged rain is rare.

Particularly on the tourist-popular south coast, it showers heavily, but usually for half an hour at most.

Beaches on the south and west coasts are best for swimming or snorkelling, while the north and east coasts are best for surfing, but the waves are big at this time and only suitable for experienced surfers.

Weather in February

February is also statistically one of the cooler months with an average temperature of 27°C.

Rain again occurs only about once every 2 to 3 days in the form of short intense showers, with the most rain in the mountains in the northeast and the least on the south coast.

Beaches on the south and west coasts are best for swimming or snorkelling, while the north and east coasts are best for surfing, but the waves are big at this time and only suitable for experienced surfers.

Weather in March

March temperatures soar to an average of 29°C and this month is the rainiest of the year according to data. However, this still means an average of 9 days a month when short intense showers will fall and the rest of the time you can expect sunny with occasional clouds.

Beaches on the south and west coasts are best for swimming or snorkelling, while the north and east coasts are best for surfing, but the waves are big at this time and only suitable for experienced surfers.

Weather in April

Temperatures on Oahu in April stay at an average of 28°C, and the wet season slowly turns into the dry season. Precipitation is mainly concentrated in the mountains of central Oahu, with rather exceptional rainfall along the coast, again only in the form of short showers.

The beaches on the south and west coasts are best for swimming in the sea or snorkelling, while the north and east coasts are best for surfing, but the waves are big at this time and only suitable for experienced surfers.

Weather in May

Temperatures in May hold steady at 29°C, rainfall is at a similar level to April, so rain is sporadic along the coasts, with more only in the mountains.

During May, surfing conditions change significantly, with big waves starting on the south coast, while the north coast calms down and is suitable for snorkelling, swimming and diving.

Weather in June

June on Oahu boasts temperatures around 30°C and very stable weather with minimal rainfall. The entire north and east coasts are ideal for swimming and snorkelling, while the south coast is ideal for surfing.

Weather in July

In July you can expect air temperatures between 30°C and 32°C and minimal rainfall. Ideal places for swimming and snorkelling are the entire north and east coasts, and for surfing the south coast.

Weather in August

August is the hottest month of the year, with an average of over 32 °C. It also rains the least on average (5 days a month) and the rains are always very short, lasting no more than a few minutes a day.

Ideal places for swimming and snorkelling are the entire north and east coasts, and for surfing the south coast.

The weather in September

September is also a typical Hawaiian summer month with normal temperatures around 31°C and very little chance of rain. Ideal places for swimming and snorkelling are the entire north and east coasts, while the south coast is ideal for surfing.

Weather in October

In October, the dry season slowly begins to turn into the wet season. Temperatures don't seem to be particularly affected, staying in the low 30s.

Rainfall increases slightly in the mountains and in the north, but prolonged, all-day rainfall is rare.

The best conditions for swimming or snorkelling are on the east and south coasts, and for surfing the season ends on the southern beaches and begins on the northern shores.

Weather in November

November temperatures "drop" to an average of 28 °C, it rains about 8 days a month, mostly in the form of short showers. Skies are mostly partly cloudy with a pleasant breeze that makes temperatures feel cooler.

The best conditions for swimming or snorkelling are on the east and south coasts, with the surfing season ending on the southern beaches and beginning on the northern shores.

Weather in December

The typically wintry month of December on Oahu means temperatures around 27°C with rain in the form of short showers about every 2nd or 3rd day.

The best conditions for swimming or snorkeling are the east and south coasts, for surfing the season ends on the southern beaches and begins on the northern shores.

Sea temperature on Oahu

The sea water on Oahu's beaches stays at very pleasant levels year-round. Temperatures are very stable on the south coast, so you can swim in water temperatures between 25 and 28°C year-round at Waikiki Beach, for example.

Water temperatures fluctuate a little more on the north coast, dropping to 24 °C during the winter and over 30 °C during the summer.