Long days of sunshine and fairly mild year-round temperatures make Hawaii an all-season destination. Most resort areas are at sea level, with average afternoon temperatures of 75°F to 80°F during the coldest months of December and January; during the hottest months of August and September, the temperature often reaches 90°F. Higher upcountry elevations typically have cooler and often misty conditions. Only at mountain summits does it reach freezing.
Moist trade winds drop their precipitation on the north and east sides of the Islands, creating tropical climates, whereas the south and west sides remain hot and dry with desertlike conditions. Rainfall can be high in winter, particularly on the north and east shores.
Most travelers head to the Islands in winter, specifically from mid-December through mid-April. This high season means that fewer travel bargains are available; room rates average 10% to 15% higher during this season than the rest of the year.
Winter on Oahu is whales (November through March) and waves (surf competitions December through February). In September, the Aloha Festivals celebrate island culture. In summer, the Islands honor the king who made them a nation, Kamehameha I, on June 11, with parades and events on all islands. Oahu's one-of-a-kind Pan-Pacific Festival follows the Kamehameha Day, bringing together hundreds of performers from Japan's seasonal celebrations. And summer swells bring waves (and surf contests) to southern beaches.
If you happen to be in the Islands on March 26 or June 11, you'll notice light traffic and busy beaches—these are state holidays not celebrated anywhere else. March 26 recognizes the birthday of Prince Jonah Kuhio Kalanianaole, a member of the royal line who served as a delegate to Congress and spearheaded the effort to set aside homelands for Hawaiian people. June 11 honors the first island-wide monarch, Kamehameha I; locals drape his statues with lei and stage elaborate parades. May 1 isn't an official holiday, but it's the day when schools and civic groups celebrate the quintessential Island gift, the flower lei, with lei-making contests and pageants. Statehood Day is celebrated on the third Friday in August (admission to the Union was August 21, 1959). Most Japanese and Chinese holidays are widely observed. On Chinese New Year, homes and businesses sprout bright-red good-luck mottoes, lions dance in the streets, and everybody eats gau (steamed pudding) and jai (vegetarian stew). Good Friday is a state holiday in spring, a favorite for family picnics.