Founder effect: Combination of genetic drift and natural selection resulting in a new genetic direction…
Hawaii is a place of extreme climates. But that’s not what a mid-western couple planning their once-in-a-lifetime, mid-winter, Hawaiian dream vacation wants to hear. Nor is it a fact that the marketers of Hawaii Visitors and Conventions Bureau spread through glossy literature. But a fact it is. Hawaii Island contains perhaps the world’s greatest concentration of climate types in its 4038 square miles. From dry, coastal, desert strand to some of the wettest spots on earth, to hot humid tropical lushness to stark, barren, snow-capped mountains, our big island offers an astonishing array of climates. You have probably heard a similar oft-quoted line, “Hawaii has 11 of the world’s 13 climate zones.” How many world climate zones are there, and which ones does Hawaii have?
Long ago the Greeks came up with a climate system that had three types: torrid, temperate, and frigid. In other words: hot, cool and cold. Hawaii easily has all three of these, but nobody uses that simple system anymore. Today, most climatologists, biologists, geographers and other professionals concerned with climate studies use the Koppen Climate Classification system. This system lists five major climate zones in the world. These zones are defined by temperature and precipitation measurements. Koppen’s five major climate zones are: 1.Arid and Semi-Arid, 2. Tropical Rainy, 3. Warm Temperate Rainy, 4. Cool Snow Forest, and 5. Polar. Hawaii has all of these zones except the Cool Snow Forest climate. But it’s more complicated than this. Within each major zone are sub-categories. Depending on the source, I have seen splits of the main categories that number 12, 13, and 14 different global sub-categories. Studies that define Hawaii’s climates recognize 10 of the Koppen sub-zones in the islands. All of these are found on Hawaii Island. To explore these ten climates, let’s start from the mountaintops with their Polar climate and work our way down in elevation to the coast where both Arid and Rainy Tropical are found.
Hawaii has the two tallest mountains on earth. When measured from their base off the ocean floor, both Mauna Kea and Mauna Loa rise over 31,000 feet high. The summits have a Polar Tundra climate. Here soil is permanently frozen. It is cold up there and the area receives an average of 15 inches or less of rain annually. Directly below the summit Polar Tundra zone are narrow bands of a Temperate climate called the Summer-Dry Cool zone. This zone covers the upper montane and sub-alpine areas circling around the peaks down to about 8500’ elevation. The upper summit area of Hualalai is also in this zone. Warmer than the Polar yet still cool enough to leave frost on the ground at times, this zone gets around 15 to 20 inches of rain a year. Still dropping down in elevation, we pick up another Temperate zone, the Summer Dry-Warm climate. This zone dominates the volcanic saddles between Kohala and Mauna Kea, or the Waimea Plains, and the Pohakuloa saddle area between Mauna Loa and Mauna Kea. As its name implies it is characterized by summer dryness and though warmer than the cool zone it has about the same annual precipitation. The next climate down makes up the largest climate zone on the island-the Continuously Wet Warm Temperate climate. It stretches from the mid-elevations of windward Kohala, along the Hamakua, Hilo, and Puna rainforests, wrapping around the island through Kau, and North and South Kona . In these mauka lands some of the largest remnants of native Hawaiian rainforest still exists between 2500 to 6500 feet elevation. The rainfall in this zone varies between 60 to 150 inches a year. Much of the precipitation falls as fog-drip creating a cloud-mist type rainforest.
Below this Temperate zone lies the Wet Tropical climate. Along the entire windward coast from sea level up to 2000 to 3000 feet in elevation lies the Continuously Wet sub-zone. Here temperatures stay warm to hot and rainfall exceeds 300 inches a year in some areas. This is the climate where the majority of the island’s residents live. The south and southeastern Kau coastal area, including Ka Lae, encompasses the Wet Tropical Summer Dry zone. Another tropical zone found is a small patch of Tropical Monsoon. On the coast near Paauilo in Hamakua is an area that receives a great majority of its heavy rainfall in the hottest months of the year. The fourth tropical sub-zone, the Tropical Wet and Dry, lies along mauka Kona. It is characterized by wet summers and dry winters. Kona is the only place in the whole state which receives its high rainfall in the kau (summer) and not hooilo (winter). Finally, we arrive at the Arid to Semi-Arid Climate. From Upolu point to Keahole at the coast, moving inland above Kawaihae to Puako, through the barren lava fields of Mauna Loa and Hualalai exists a Hot Semi-Desert. Along the North Kona, South Kohala coast, from Kiholo to Kawaihae, right along the coastal strand exists a Hot Desert climate. With less than 10 inches of rain a year and hot, hot days, this zone benefits well from the calm, clear, and invigorating ocean waters. If not for the cooling ocean breezes that come ashore, these lands of resorts and beach houses would be a miserable place to be.
On one island in the tropics we have 10 different climate zones. Whether it’s 10 of 12 or 10 of 13 or 10 of 14, it is still impressive and probably unequalled anywhere else on earth for an area of equal size. From Arid to Wet Tropical to Cool Temperate to Polar Tundra, our island is a land of all seasons. So if you ever tire of the same old torrid coastal weather at the coast, pick a zone, take a drive, and experience a climatic change.