By A.R. Royo
With a diverse, spectacular climate, Hawaii has almost perfect weather year round. Most of the year, the coasts have comfortable daily temperatures between the mid-70s and mid-80s. Hawaii is the only state in the U.S. that has never recorded a sub-zero temperature.
Since Hawaii has only 2 seasons-Summer (May through October) and Winter (November through April), you will experience more heat and humidity variation from elevations and windward-leeward coasts, than you will due to the seasons. If you’re curious what the weather is like right now, check out the Forecast of Today’s Weather in Hawaii.
The Amazing Geography of Hawaii
The inhabited Hawaiian Islands are only twelve- to sixteen-hundred miles north of the equator and are between 19 and 23 degrees north latitude. This fortuitous circumstance of geography means the sun is high in the sky all year round, providing temperatures that heat both the land and the nearby ocean. The temperature varies from only about 75 degrees to 83 degrees between Winter and Summer.
A warm ocean surrounding the Hawaiian Islands keeps the atmosphere above relatively warm. There are other contributing factors to Hawaii’s delightful, tropical climate besides the ocean and its proximity to the equator: namely, the trade winds and Hawaii’s many volcanic mountains.
The Heights of Hawaii
Hawaiian mountains, formed millions of years ago, affect Hawaii’s weather and account for the variations in weather, both from island to island and on the same Island.
When moist, warm air meets mountain slopes along windy coasts, the air is forced to ascend, expand and cool (this is known as orographic lift). This forms heavy clouds and causes rainfall along the windward slopes. When this air reaches the leeward slopes, it descends, condenses, and warms, making leeward coasts generally sunnier, warmer and drier.
The Trade Winds of Hawaii
Trade winds coming from northeast of Hawaii average 12 mph. These winds occur around 90 percent of the time in the summer and around 50 percent of the time in the winter. They keep humidity at a minimum and ensure pleasant temperatures, especially on the northeastern coasts of the Hawiian Islands.
These cooling winds are created because warm air rises near the equator, flows northward through the upper atmosphere, then cools. Becoming denser as it cools, it descends back to the earth’s surface where it back flows toward the equator to replace more rising, warm air. This creates cool northeasterly breezes moving along the ocean’s surface, and over the Hawaiian Islands.
Oahu Weather and Climate
Like the other Hawaiian Islands, Oahu’s tropical climate is affected more by the ranges of elevation and geographic location than it is by the seasons. Its rain-bearing trade winds are obstructed by Oahu’s 2 parallel mountain ranges – Ko’olau (reaching 3,105 feet), and Wai’anae (reaching 4,020 feet).
Thus Honolulu, Waikiki, and Ko Olina on the southern and western sides of the island are dry and warm. Conversely, Kailua and Aeia on the windward side, and The North Shore, near Haleiwa (a popular surf town), are cooler and wetter.
Dangerous sea conditions are mostly brought by Winter to Oahu’s renowned surfing beaches along the north shore. The surf is well-suited to big-wave competitions, but risky for the inexperienced. Check out the current Oahu 10-Day Weather Forecast.
Maui Weather and Climate
On Maui, with its 2 volcanic mountains, and separated by the central valley, you’ll encounter everything from barren lunar-like desert atop 10,320-foot Mt. Haleakala, to lush tropical creepers and wild ginger east toward the Hana coast, to bamboo forests, eucalyptus and pines moving upcountry. Considering its lush forests, it doesn’t come as much of a surprise that Pu’u Kukui (the summit of the West Maui Mountains) holds the U.S. rainfall record at 739 inches in 1982. Have a look at the variations in the island’s climate: Hawaii Weather Forecast Maui.
Paia and Haiku, located near Maui’s north shore, are world-class kite boarding and windsurfing destinations, and they have excellent trade winds and beach access. Maui’s south and west shores provide almost year-round sunshine, dry weather and fantastic beaches along the resort areas of Makena, Wailea, Kihei, Lahaina, Kaanapali and Kapalua.
Big Island Weather and Climate
On the Big Island, there are 5 shield volcanoes, creating the most diverse climate in Hawaii. The Big Island also contains ten of ten of the world’s fifteen climate zones. Hilo, on the windward side, is the wettest city in the U.S., averaging more than 130 inches of rain per year. Check out the current Big Island 10-Day Weather Forecast.
The leeward coast is usually sunny and warm, averaging as little as 5 inches each year. Kailua, Kona, and Kohala include resort areas on these dry coasts. Snow, not usually associated with the tropics, falls at Mauna Kea (Hawaii’s highest point at 13,796 feet) and Mauna Loa (location of the U.S.’s only active volcano), Kilauea, in some winter months.
Kauai Weather and Climate
Kauai is a small, circular island, formed by a single eroded volcano. It’s highest peak at Mount Wai’ale’ale reaches 5,243 feet near its center. With more than 460 inches of rain per year, this peak is regarded as the wettest place on the planet. Just 20 miles southwest of the extremely wet mountain is the Kekaha coastal area, which averages less than 20 inches of rain per year.
The spectacular Na Pali Coast, Princeville, and idyllic Hanalei, with their lush, tropical environs on the north shore provide unparalleled opportunities for nature adventure. The primary resort areas, Poipu and Koloa, are conveniently located on the warmer, drier south shore of Kauai. Take a look at the variations in the island’s climate: Hawaii Weather Forecast Kauai