One of the factors that make Hamakua a place of relatively low population in modern times is the weather.  The present extended period of unusually low rainfall notwithstanding, the windward reaches of our district are often included in Honolulu-based weather forecasts as the only place in the Islands to have clouds and rain, while the rest of the State enjoys sunny weather.  The wording often is something like; "Most of the Islands will have clear skies except for the windward side of the Big Island." 

This sort of reputation has slowed migration to our area, because these days, when people have a choice, they often will select drier, warmer, less windy places to live in.  When people lived off the land, they knew that life depends on water.  Ample rainfall dictated the areas in which food could be grown, and therefore, where they could survive: Ola i ka wai a ka `opua, it is said – There is life in the water from the clouds.

Waipi`o and Waimanu Valleys were among the earliest places of settlement in these Islands, by virtue of their reliable streams.  When, after 600 years of human habitation in Waipi`o, permanent places of residence began to be established along the coastal areas above the Valley, the usual rainfall was sufficient for food crops.  If dry spells such as we have now came along, there

was then water in the numerous gulches -- kahawai – to help out.  These days, the only gulches in Hamakua that continuously carry water are those that are fed by diverted water – the leaky Lower Hamakua Ditch, or the water taken out of Lalakea Stream to the Lalakea Reservoir and passed on to Waiulili Stream.  The forests above have been so degraded by cattle and other agents of deforestation that the sponge-like qualities they had are mostly gone.  Just a few generations ago, many of Hamakua's kahawai had continual flow, fed during dry times by moisture held and gradually released by the saturated ground under the trees, ferns, shrubs and mosses of the native Hawaiian forest.

A quick overview of the elements of weather as it appears in our part of the world includes precipitation, temperature, and wind.  Rainfall over the ocean around our Island is usually 25 to 30 inches annually.  The moisture-laden trade winds interact with the highly varied land forms of the volcanic slopes that face into them to produce rainfall as much as 10 times more than the open sea gets, or as little as half that amount.  Because Hamakua includes such a range of climate zones, it has a great range of temperatures and precipitation.  The greatest rainfall occurs between 2,000 and 4,000 feet in elevation, where 120 inches annually are not uncommon; the summits of Mauna Kea and Mauna Loa (also parts of Hamakua) usually get less than 25 inches of rain a year.   In the saddle between our giant volcanic mountains, yearly rainfall is about 20 inches. Drought is not unknown, obviously, and although it rarely affects more than one part of the Island at a time, the probability of serious drought somewhere on the Island during any given 10-year period is greater than 90 percent.

The consistent mild temperatures of Hawai`i is one of its most favored and well-known characteristics.  The average temperatures of the Island near sea level range from 72 to 75 degrees F.  Temperature drops with elevation, of course, with an average loss of 3.6 degrees for each 1,000 feet; Hamakua, with its elevations ranging from 0 to 13, 796 feet above sea level, has places that freeze every night.  The weather observatory on Mauna Loa (in part of Hamakua), at 11,000 feet, has an average temperature of 45 degrees.  The seasonal range of temperature is four to eight degrees, while the average difference between daily high and low temperature is ten to twenty degrees.  This means that the there is more variation in the temperature between night and day than there is between the hottest and coldest day in any given place.

The prevailing wind, throughout the year, is the east northeasterly trade wind.  So consistent are these winds that the part of the Island they impact directly are known as "windward" even during times when the winds come from other directions.  They are in effect about 70% of the time throughout the year, but are present only 50% of January.  In July, they blow more than 90% of the time.  When the trades aren't affecting us, we may enjoy the unusual experience of being in the wind shadow of Mauna Kea when southerly or westerly winds blow.  Sometimes, though, Kona winds howl destructively down the mountain slopes and through the backs of the valleys.  Then it can be said, Hu ka makani  – "The wind blows a gale. " 

Kindly as the weather in Hamakua can be, those who have lived here for a while know that it can also test our abilities to handle wild events that disrupt our usual patterns.  While those experiences lead some to seek milder conditions elsewhere, they produce a certain sense of appreciation in others, who understand that forces more powerful than we are can tell us something about who we are and how we must shape our lives to relate to those elements.

A hui hou,

Dr. Hugh Montgomery