- Temperatures: The annual average temperature is around 75 °F (24 °C), with little seasonal variation. The average daily high temperature ranges from 80 to 85 °F (27 to 29 °C) during the summer (July–September) and from 75 to 80 °F (24 to 27 °C) during the winter (December–March). The average daily low temperature ranges from 65 to 70 °F (18 to 21 °C) during the summer and from 60 to 65 °F (16 to 18 °C) during the winter.
- Rainfall: Oahu receives an average annual rainfall of around 40 inches (102 cm), with significant variations between different parts of the island. The windward (northeastern) coast is much wetter than the leeward (southwestern) coast. For example, the annual average rainfall at Honolulu International Airport on the leeward side is around 20 inches (51 cm), while at Kahuku Point on the windward side it is over 80 inches (203 cm). The wettest months are typically November to March, while the driest months are typically June to August.
- Humidity: Oahu has a relatively humid climate, with average relative humidity ranging from around 65% during the afternoon to around 85% during the morning.
- Sunshine: Oahu has an average of around 260 sunny days per year. The sunniest months are typically May to August, while the cloudiest months are typically November to March.