Best months to visit
JanuaryFebruaryNovemberDecember
April-May and September-October are the sweet spot — warm sea, low rain on the south shore, less crowded than the December-March winter peak. Surfers target November-February for the North Shore. June-August is reliably dry and warm but more humid and crowded.
Best for
Beach
April-October — Waikiki and the south shore have driest weather, calm warm sea (25-27 °C), and full beach service.
Hiking
April-June and September-November — Diamond Head, Koko Head and the Koolau ridge trails are coolest and driest then; midsummer middays on exposed ridges hit 32-34 °C.
Sightseeing
Year-round — Pearl Harbor, Iolani Palace and downtown Honolulu work in any weather; April-May and September-October hit the sweet spot of low rain, warm sea, and lighter crowds.
Climate notes
- Northeast trade winds: blow 70-90 % of summer days at 10-20 knots, defining Oahu's wet windward (NE — Kailua, Kaneohe) and dry leeward (SW — Honolulu, Waikiki) sides.
- Wet winter (November-March): Kona lows and Pacific fronts bring most of Oahu's rain; Honolulu averages 75-90 mm per month, while the Koolau windward slopes can see 150-300 mm.
- Dry summer (May-September): leeward Honolulu drops to 35-50 mm per month and humidity is moderate; the trade winds keep daytime air comfortable at 26-30 °C.
- North Shore winter swell (October-April): open-ocean storm energy from the North Pacific produces 6-12 m faces — the world's premier big-wave season at Pipeline, Sunset, Waimea.
- Hurricane season (June-November, peak August-October): Hawaii sits at the edge of the Central Pacific basin; direct hits on Oahu are very rare but Tropical Storm advisories occur most years.
- Kona winds: occasional southwesterly winds that flip the windward/leeward pattern — bring humid, hazy weather and mostly affect winter Honolulu.
Temperature (min / max °C)
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Rainy days per month
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Sunshine hours per month
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Regional notes
- Honolulu / Waikiki (south shore, leeward): driest part of the island. Calm summer surf, modest winter swell, sunny most days.
- North Shore (Haleiwa, Pipeline, Sunset Beach): legendary winter big-wave coast (October-April). Calm enough for swimming and snorkelling May-September.
- Kailua and Lanikai (windward east): catch the trades full force; turquoise water, white sand, but occasional brisk wind. Wettest beach corridor.
- Koolau Range and Pali (interior windward slopes): orographic rainfall hotspot — Manoa Valley behind Honolulu averages 4 m of rain a year despite Waikiki's modest 500 mm.
- West coast (Ko Olina, Makaha): leeward, drier than Waikiki, with a longer afternoon-sun exposure.
Frequently asked questions
When is the best time to visit Oahu?
April-May and September-October — outside hurricane peak, Waikiki has reliable sun and warm sea, and crowds are lighter than the December-March holiday season.
When is the North Shore at its biggest?
December-February — open-ocean swells from the North Pacific produce 6-12 m faces at Pipeline, Sunset Beach and Waimea. Beginners and swimmers should switch to the south shore in winter.
Does Oahu have a hurricane season?
Yes — June-November, peak August-October. Direct hits on Oahu are rare in any given year but Tropical Storm watches happen most seasons. Modern forecasting gives several days warning.
Why is Waikiki so much drier than the rest of Oahu?
The Koolau Range catches NE trade-wind moisture as orographic rain on its windward slopes; Waikiki sits in the rain shadow on the leeward south side. Manoa Valley behind Honolulu can get 4 m of rain a year while Waikiki gets about 0.5 m.
Can I see whales in Oahu?
Yes, December-April — humpback whales migrate from Alaska to breed and calve in Hawaiian waters. Best viewing from Makapuu Point, Diamond Head and West Side boat tours; peak season is January-March.
Is the trade wind always blowing?
About 70-90 % of summer days and roughly half of winter days. When trades fail (Kona conditions), the air feels heavier, vog from Big Island volcanic activity may drift north, and sea conditions can flip — south shore choppier, north shore calmer.
What is the water temperature in Oahu in February?
About 24-25 °C — comfortable for swimming. Most people swim without a wetsuit; surfers in winter often use a thin (2 mm) shorty for early morning sessions.
Is Oahu crowded year-round?
Peak crowding is mid-December through early January (winter holidays) and mid-June through early August (US summer). Shoulder seasons (April-May, September-October) are noticeably calmer with the same warm weather.
Climate data: Open-Meteo · 2020–2025