Oahu Hawaii Weather

If you read my home page you know I’m partial to Oahu Hawaii weather with Honolulu’s average yearly lows and highs of 71 and 84 degrees Fahrenheit (22, 29 Celsius).I don’t claim to be a weather expert, but I’ll try to paint an accurate picture of Oahu weather monthly and steer you to reliable daily and weekly Oahu weather forecasts.

Then… YOU can decide if Oahu’s climate is YOUR definition of paradise.

Oahu Weather Seasons

The Hawaiian Islands are perfectly placed in the Central Pacific Ocean where cooling trade winds prevail most of the time and Honolulu’s average temperature only varies about 7-8 degrees all year.

Hawaii’s official calendar seasons are the same as the US mainland: Spring March 20, Summer June 21, Fall September 22 and Winter December 21.

Yet, since the temperature only changes a few degrees, there are really only two basic seasons… the hotter drier season from April through September and the rainier cooler season from October through March.

So what does Oahu Hawaii weather feel like?

I know visitors who came here and literally made a decision to move to the island on a whim. Some literally never go back home. I ran into a high school classmate from California at an Oahu restaurant who said he came to Hawaii for a vacation and immediately decided to move. This is a guy who had a mainland business and is an expert downhill snow skier. He now paddles outrigger canoe!

---

Here’s an August chart of average temperatures based on the National Oceanic and Atmospheric Administration’s (NOAA) 1981-2010 Normals Data. The chart compares Oahu Hawaii weather to US mainland coastal cities and Tahiti in French Polynesia. Tahiti’s comparison month is February, summertime in Tahiti.

I do recommend French Polynesia’s gorgeous calm lagoons though… been there, done that, would do it again!

I rounded some of NOAA’s figures and converted them to Celsius for ease of reference so figures may not be exact. I am not affiliated with NOAA.  

OAHU HAWAII WEATHER COMPARISONS

Is Oahu Hawaii Weather Too Hot and Humid?

I doubt you’ll find better ocean temperatures or humidity percentages than Oahu Hawaii weather offers during the hottest time of year, July, August and September.

Many locals do not have central air conditioning, just ceiling fans or portable fans. I do recommend having an air conditioned car. You will welcome it in the summer.

Locals wish for cooler weather when temperatures approach the mid 80’s (29 C) or the trade winds cease. When trade winds stop and Kona winds from the Big Island bring hazy skies with hovering VOG (volcanic smog), the heat and humidity can be oppressive.

NOTE: Extreme lows in the winter can drop to the upper 50s F (14 C) and extreme highs in the summer can reach the low 90s F (34 C). Bring a light jacket like a windbreaker if you are visiting in the wintertime.

Rain, Rain Go Away?

Maybe you like rain, maybe you don’t, so it’s important to remember that rainfall differs significantly around the island and increases at higher elevations. Temperatures also cool with elevation.

I know people who had their entire week’s vacation ruined by rain! The rainy season begins about October and starts tapering off in April. 

HINT: You and your camera may get wet when hiking. Plastic rain ponchos are light and can be purchased at some convenience and grocery stores.

Let’s get real though… a lot of times the rain comes in passing showers, and/or in the overnight hours… unless there is tropical storm looming which is more likely in the rainy season.

In Waikiki you will see visitors at the beach jumping up when it starts raining while locals stay put. The locals know it’s a passing shower that will be over in a couple of minutes. A frequent strange occurrence is feeling showers when there are no clouds directly above…It’s just the trade winds blowing rain towards you from clouds off in the distance.

Oahu Monthly Temperature and Rain Amounts

Oahu Hawaii Weather Cautions

TROPICAL STORMS: When there is a tropical storm torrential downpours can result in severe flooding anywhere on the island. Traffic nearly comes to a standstill due to extremely poor visibility. I have driven when the water was half way up the hub caps on my 4-wheel drive truck and a newly-formed river was rushing across the highway.

HURRICANES: A direct hit from hurricanes is rare in Hawaiian waters but can happen and most likely would be between June and November.  If a hurricane is offshore it affects the islands with large pounding waves, strong winds and torrential rain.

I felt the fringes of Category 4 Hurricane Iniki in 1992 in Ewa Beach. I still remember the trees in my front yard looked like someone used a blow dryer on them for several weeks after the storm. Kauai took a direct hit resulting in several deaths and many home losses.