Ka Lani:  The Sky 

The Hawaiian Islands are blessed with some of the most temperate skies in the world.  Although they lie at latitudes 19-22° N of the Equator, equivalent to some of the hottest, muggiest places on earth, such as Calcutta, Cuba and the Yucatan, Mexico, these Pacific islands bask in pleasant sunshine and refreshing breezes nearly year round, rarely reaching temperatures above 90° or below 55° in low elevation zones.  The average year round temperature in the drier leeward zones is a pleasant 75°.

This good fortune of Hawai‘i actually stems from a confluence of good fortunes:  its ocean setting, its position in global wind patterns and its volcanic mountains.  The cool winds blowing off the ocean act to cool the land’s solar radiation during daylight hours.  These “trade winds” are generated by a massive, relatively stable, high-pressure system that sits to the northeast of the islands, blocking the unstable high and low pressure systems and bad weather from the west.  Also by chance, a wind cell from the equator descends directly over the islands bringing warm air that blocks air rising and cooling below it, thus creating cloud blankets.  As the trade winds rise upon meeting Hawai‘i’s volcanic mountains they cool and precipitate, falling as rain and mist on the mountains and valleys.

Because of these wind patterns Hawai‘i remains pleasant most of the year.  However, during the winter months the stable, high-pressure system shifts slightly south, sometimes allowing the unstable fronts to enter from the west.  At such times the islands can experience rainstorms, high winds and drops in temperature.  These storms were called “kona” by the Hawaiians, signifying winds from a non-NE direction.

Thus, Hawai‘i has two seasons; a relatively dry, stable trade winds summer (kau wela) and a rainy, shifting wind winter (ho‘oilo).  These seasons correspond to the months of May through October for summer, and November through April for winter.  However, even during “winter” the weather is mostly sunny and calm, with rain falling mainly in the mountains and windward sides of the islands.