Oahu Weather by Month
Oahu has a warm tropical climate throughout the year, with relatively small temperature changes between seasons. Based on the weather data provided, average daytime highs range from about 77°F to 86°F, while nighttime lows stay between 63°F and 70°F.
Rainfall varies more noticeably by month, with the wettest conditions generally occurring from November through March and the driest period around July and August. Daylight also changes only slightly, from about 11 hours in winter to 13.5 hours in summer.
Oahu Weather by Month
You can click the image below to view the full-size weather chart for Oahu.
January – Mild, Warm and Moderately Wet
Average high: 77°F (25°C)
Average low: 63°F (17°C)
Rainfall: 1.82 inches (46.2 mm)
Water temperature: 76°F
Daylight: 11 hours
January is one of the cooler months on Oahu, although temperatures remain comfortably warm compared with most destinations. Average daytime temperatures reach around 77°F (25°C), while nighttime temperatures fall to about 63°F (17°C).
Ocean water averages around 76°F, making swimming and other water activities possible throughout the month.
Rainfall averages 1.82 inches (46.2 mm), with about 5 rainy days during the month. With 11 hours of daylight, there is still plenty of time for outdoor activities and sightseeing.
Best for:
- Comfortable sightseeing
- Swimming and beach activities
- Hiking in cooler weather
- Beach walks
February – Mild and Pleasant
Average high: 77°F (25°C)
Average low: 63°F (17°C)
Rainfall: 1.40 inches (35.5 mm)
Water temperature: 76°F
Daylight: 11.5 hours
February has very similar air temperatures to January, with average highs of 77°F (25°C) and lows around 63°F (17°C). Ocean temperatures remain around 76°F, providing comfortable conditions for swimming and water activities.
Rainfall decreases to about 1.40 inches (35.5 mm), with around 4 rainy days. Daylight increases to 11.5 hours.
Best for:
- Beach activities
- Swimming and snorkeling
- Hiking
- Scenic drives
March – Warm and Comfortable
Average high: 79°F (26°C)
Average low: 64°F (18°C)
Rainfall: 1.56 inches (39.6 mm)
Water temperature: 76°F
Daylight: 12 hours
March brings a small increase in air temperature, with average highs of 79°F (26°C) and lows of 64°F (18°C). The ocean remains around 76°F, so visitors can enjoy swimming and snorkeling without major seasonal changes in water temperature.
Rainfall averages 1.56 inches (39.6 mm), spread across about 5 rainy days.
Best for:
- Swimming and snorkeling
- Hiking and nature trails
- Beach visits
- Outdoor photography
April – Warm and Drier
Average high: 79°F (26°C)
Average low: 66°F (19°C)
Rainfall: 1.08 inches (27.4 mm)
Water temperature: 76°F
Daylight: 12.5 hours
April is warm and relatively dry on Oahu. Average highs reach 79°F (26°C), while nighttime temperatures remain around 66°F (19°C). The average ocean temperature is about 76°F.
Rainfall drops to 1.08 inches (27.4 mm), while daylight increases to 12.5 hours.
Best for:
- Beach days
- Swimming
- Hiking
- Road trips
May – Warm, Dry and Sunny
Average high: 81°F (27°C)
Average low: 66°F (19°C)
Rainfall: 0.78 inches (19.7 mm)
Water temperature: 78°F
Daylight: 13 hours
May marks the beginning of a warmer and drier period. Average highs reach 81°F (27°C), while ocean temperatures rise to around 78°F.
Rainfall is relatively low at 0.78 inches (19.7 mm), with approximately 3 rainy days.
Best for:
- Swimming and snorkeling
- Beach activities
- Surfing
- Long days of sightseeing
June – Hot, Dry and Long Days
Average high: 84°F (29°C)
Average low: 68°F (20°C)
Rainfall: 0.65 inches (16.5 mm)
Water temperature: 79°F
Daylight: 13.5 hours
June brings warmer temperatures and some of the longest days of the year. Average highs reach 84°F (29°C), while ocean temperatures average about 79°F.
Rainfall averages only 0.65 inches (16.5 mm), making June one of the drier months.
Best for:
- Swimming and snorkeling
- Surfing
- Hiking
- Beach vacations
July – Warm, Very Dry and Sunny
Average high: 84°F (29°C)
Average low: 70°F (21°C)
Rainfall: 0.50 inches (12.7 mm)
Water temperature: 80°F
Daylight: 13.5 hours
July is one of the warmest and driest months on Oahu. Average highs remain around 84°F (29°C), while the ocean reaches about 80°F.
Rainfall falls to just 0.50 inches (12.7 mm), making July particularly suitable for outdoor and water activities.
Best for:
- Beach vacations
- Snorkeling and swimming
- Surfing
- Outdoor adventures
August – Hot, Dry and Bright
Average high: 86°F (30°C)
Average low: 70°F (21°C)
Rainfall: 0.51 inches (13 mm)
Water temperature: 80°F
Daylight: 13 hours
August is one of the hottest months on Oahu, with average highs around 86°F (30°C). Ocean temperatures are also very warm at approximately 80°F.
Rainfall remains extremely low at about 0.51 inches (13 mm), with around 2 rainy days.
Best for:
- Swimming and snorkeling
- Surfing
- Beach activities
- Tropical outdoor adventures
September – Warm and Mostly Dry
Average high: 86°F (30°C)
Average low: 70°F (21°C)
Rainfall: 0.93 inches (23.6 mm)
Water temperature: 81°F
Daylight: 12.5 hours
September remains hot and tropical, with average highs of 86°F (30°C). It also has some of the warmest ocean water of the year, averaging around 81°F. (Current Results)
Rainfall increases slightly to 0.93 inches (23.6 mm), while daylight remains generous at 12.5 hours.
Best for:
- Beach trips
- Swimming and snorkeling
- Surfing
- Hiking early in the day
October – Warm and Increasingly Wet
Average high: 84°F (29°C)
Average low: 70°F (21°C)
Rainfall: 1.21 inches (30.8 mm)
Water temperature: 81°F
Daylight: 11.5 hours
October remains warm, with average highs around 84°F (29°C). The ocean stays at approximately 81°F, making it one of the warmest months for swimming.
Rainfall increases to 1.21 inches (30.8 mm), with about 3 rainy days.
Best for:
- Beach activities
- Swimming
- Hiking
- Surfing
November – Warm, Mild and Wetter
Average high: 81°F (27°C)
Average low: 68°F (20°C)
Rainfall: 1.73 inches (43.9 mm)
Water temperature: 79°F
Daylight: 11 hours
November remains pleasantly warm, with average highs of 81°F (27°C). Ocean temperatures average around 79°F, so swimming is still comfortable for many visitors.
Rainfall increases to 1.73 inches (43.9 mm), with approximately 5 rainy days.
Best for:
- Swimming
- Hiking between showers
- Scenic drives
- Beach walks
December – Warm, Mild and Wet
Average high: 79°F (26°C)
Average low: 66°F (19°C)
Rainfall: 1.56 inches (39.7 mm)
Water temperature: 77°F
Daylight: 11 hours
December is one of the cooler months on Oahu, but the weather remains warm. Average highs reach 79°F (26°C), while ocean temperatures average about 77°F.
Rainfall averages 1.56 inches (39.7 mm), with around 5 rainy days. The combination of warm air and relatively warm ocean water makes December suitable for a tropical winter getaway.
Best for:
- Winter beach vacations
- Swimming
- Hiking
- Escaping cold winter weather
Oahu Weather by Month Table
| Month | Avg High °F (°C) | Avg Low °F (°C) | Rainfall (inches) | Water Temperature | Daylight (hours) |
|---|---|---|---|---|---|
| January | 77°F (25°C) | 63°F (17°C) | 1.82 | 76°F | 11 |
| February | 77°F (25°C) | 63°F (17°C) | 1.40 | 76°F | 11.5 |
| March | 79°F (26°C) | 64°F (18°C) | 1.56 | 76°F | 12 |
| April | 79°F (26°C) | 66°F (19°C) | 1.08 | 76°F | 12.5 |
| May | 81°F (27°C) | 66°F (19°C) | 0.78 | 78°F | 13 |
| June | 84°F (29°C) | 68°F (20°C) | 0.65 | 79°F | 13.5 |
| July | 84°F (29°C) | 70°F (21°C) | 0.50 | 80°F | 13.5 |
| August | 86°F (30°C) | 70°F (21°C) | 0.51 | 80°F | 13 |
| September | 86°F (30°C) | 70°F (21°C) | 0.93 | 81°F | 12.5 |
| October | 84°F (29°C) | 70°F (21°C) | 1.21 | 81°F | 11.5 |
| November | 81°F (27°C) | 68°F (20°C) | 1.73 | 79°F | 11 |
| December | 79°F (26°C) | 66°F (19°C) | 1.56 | 77°F | 11 |
20 FAQs About Oahu Weather
1. What is the weather like in Oahu year-round?
Oahu has a warm tropical climate year-round. Average high temperatures generally range from about 77°F to 86°F, while average lows range from 63°F to 70°F.
2. What is the hottest month in Oahu?
August and September are the hottest months in the provided data, with average highs of about 86°F and nighttime lows around 70°F.
3. What is the coldest month in Oahu?
January and February are the coolest months, with average highs around 77°F and lows around 63°F.
4. Does Oahu get cold in winter?
Oahu does not usually experience cold winter weather. Even in January and February, average daytime temperatures are around 77°F, making winter comfortable for outdoor activities.
5. What is the best month to visit Oahu for warm weather?
June through September offers some of the warmest weather, with average highs between 84°F and 86°F.
6. What is the driest month in Oahu?
July is the driest month in the provided data, with average rainfall of only 0.50 inches.
7. What is the rainiest month in Oahu?
January has the highest rainfall in the provided data at about 1.82 inches, followed by November at 1.73 inches.
8. Does it rain a lot in Oahu?
Oahu generally does not receive large amounts of rainfall compared with many tropical destinations. Rainfall varies by month, with about 0.50 to 1.82 inches in the provided data.
9. What month has the most daylight in Oahu?
June and July have the most daylight, at approximately 13.5 hours per day.
10. How many hours of daylight does Oahu get in winter?
Oahu receives about 11 hours of daylight per day during January, November and December.
11. Is Oahu warm in January?
Yes. January is warm by most standards, with an average high of 77°F and an average low of 63°F.
12. Is Oahu hot in August?
Yes. August is one of the hottest months, with an average high of 86°F and an average low of 70°F.
13. Is October a rainy month in Oahu?
October is somewhat wetter than the summer months, with about 1.21 inches of rainfall and approximately 3 rainy days.
14. Is November a good month for outdoor activities in Oahu?
November remains warm, with an average high of 81°F. However, rainfall increases to about 1.73 inches, so visitors should be prepared for occasional showers.
15. What is Oahu weather like in December?
December is mild and warm, with an average high of 79°F and an average low of 66°F. Rainfall averages about 1.56 inches.
16. What is Oahu weather like in spring?
Spring temperatures gradually become warmer, with average highs increasing from about 79°F in March and April to 81°F in May. Rainfall generally decreases during this period.
17. What is Oahu weather like in summer?
Summer is warm, relatively dry and sunny. From June through August, average highs range from 84°F to 86°F, while rainfall stays below 0.7 inches per month in the provided data.
18. What is Oahu weather like in fall?
Fall remains warm, but temperatures gradually decrease from about 86°F in September to 79°F in December. Rainfall generally becomes more frequent toward November and December.
19. Does Oahu have good weather for beach activities?
Yes. Warm temperatures throughout the year make Oahu suitable for swimming, snorkeling, surfing and other beach activities. Summer generally has warmer and drier conditions.
20. What month has the best weather in Oahu?
Weather preferences vary, but the provided data shows that June through September combine warm temperatures, relatively low rainfall and long daylight hours.
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