Hawaii Weather 10 Day Forecast for all Hawaiian Islands, with conditions and climate for Honolulu, Oahu, Maui, Kauai and Big Island. Hawaii weather today forecast includes satellite pictures, news, tsunami warnings.
Hawaii has a spectacular, diverse climate and enjoys nearly perfect weather. Its daytime temperatures along the coasts generally range from only the mid-70s to the mid-80s most of the year. Hawaii is the only state in the U.S. that has never recorded a sub-zero temperature.
Since Hawaii has only two season - Summer (May through October) and Winter (November through April), you will experience more temperature variation between elevations and windward-leeward coasts, than you will between the seasons.
Hawaii coastal temperatures can sometimes dip into the 60s during mid-winter and rise into to the 90s in mid-summer. Hawaii's heaviest rains occur during winter-month storms, often riding Kona winds, which uncharacteristically blow from the southeast. Flash flooding is not uncommon at such times. Hurricane season in Hawaii is June through November. Hurricanes are rare, occurring only about once every 10 years.
Hawaii contains two of the wettest places on earth (Kauai and Maui), averaging over 400 inches of rain annually, and some of the driest places on the planet, averaging less than 5 inches annually. Snow is rare in Hawaii, but occasionally occurs at elevations above 8,000 feet on the Big Island's Mauna Kea and Mauna Loa, and Maui's Mt. Haleakala.
Hawaii's Beneficial Geography
Located between 19 and 23 degrees north latitude, the inhabited Hawaiian Islands lie only 1,200 to 1,600 miles north of the equator. This fortuitous circumstance of geography means the sun is high in the sky year round, creating temperatures that warm both the land and the surrounding ocean, which varies in temperature from only about 75 degrees to 83 degrees between winter and summer.
Such a warm surrounding ocean keeps the atmosphere above the Hawaiian Islands relatively warm. But two other factors contribute to Hawaii's reputation as a tropical paradise with diverse microclimates: Hawaii's trade winds, and Hawaii's numerous volcanic mountains.
Hawaii Volcanic Mountains
The mountains of Hawaii, formed millions of years ago though volcanic eruptions from the ocean floor - as the Pacific Plate moves slowly northwest over a hot spots in the earth's mantle - affect Hawaii's climate and account for the variations in weather from both island to island and on the same Island.
When moist, warm air meets mountain slopes along windward coasts, the air is forced to rise, expand and cool (orographic lift), forming clouds, and causing rainfall up the windward slopes. When this air reaches the leeward slopes, it descends, condenses and warms making leeward coasts generally sunnier, warmer and drier.
Hawaii Trade Winds
In Hawaii, the northeast trade winds, averaging 12 mph, occur about 90% of the time in the summer and about 50% of the time in the winter. They keep humidity at a minimum and ensure moderate temperatures, especially on the windward, unlike other tropical islands closer to the equator.
These cooling winds are created because warm air rises near the equator, flows northward through the upper atmosphere, and cools. Because it becomes heavier as it cools, it falls back to the earth's surface at about 30 degrees latitude, where it flows back toward the equator to replace more rising warm air. This creates cool breezes moving from the northeast to the southwest along the ocean's surface, and over the Hawaiian Islands.
This is a global phenomenon recognized by early mariners, who used it to cross the world's oceans in wooden sailing ships to trade their wares. The trade winds received their name from these mariner-traders of yore.