Climate, Weather, Wind and Ocean currents

Maui is a tropical island with a fairly mild year round climate tempered by the Pacific ocean, which makes the temperature stay consistent with only a few degree change.  Maui has two seasons which are summer and winter and the temperatures of summer and winter are separated by only a few degrees.  Summer is called "Kau", and takes place from May-Oct.  The average day time temperature is 85'F or 29'C, and the nights are10'F or 5'C lower than the day time. The winter months are from Nov-Apr and the winter is called Ho'oilo.  The average day time temperature is 78'F or 25.6'C and the night time temperatures are also 10'F or 5'C like the summer temperatures, which makes Maui an ideal place for vacation because of the consistency in the temperatures from summer to winter.

Due to the prevailing trade winds, most rainfall hits the north or the northeast facing shores, leaving the south and the south west areas relatively dry.  The dominance of the winds and the influence of the terrain give special character to the climate of the island.  Completely cloudless skies are extremely rare, ever though much of the cloud cover is confined to the mountain areas and the Windward slopes while the leeward lowlands have only a few scattered clouds.

Rainfall is highly variable from one year to another in Maui.  In areas where the rainfall is very high and the monthly average could exceed 10 inches, these same areas may only get 1-2 inches on the same month the very next year. Most of the rain falls on the windward slopes of the island (north, northeast) and the leeward lowlands get the remaining of the precipitation.


www.kiheivacation/maui/maui-climate/

The weather at the summit of Haleakala crater is unpredictable, the temperatures commonly range from 40'F-65'F, but can also reach below freezing at any time of the year.  Haleakala's summit is 10,023' in elevation, and if you start from the bottom of this massive volcanic crater, the temperature could be at 80'F which is the town of Kipahula and the summit could get to 30'F. As you gain altitude you can feel the air get cooler and the wind blows with more strenghth.

Haleakala is directly effected by the presence and movement of trade wind inversion, where moist surface air grades rapidly dry upper air, which gives Haleakala's climate four different climate zones.  The first zone is the marine zone which is below 3,600 ft, this zone contains moist well mixed air that comes in contact with oceanic moisture.  The next zone is the fog zone, which is approximately between 3,600ft and 5,400ft, cloud layer in frequent contact with the surface.  The transitional zone is next and this zone is betweem 5,400ft and 7,200ft, this zone has a high variable climate.  The last zone is the arid zone which is above 7,200ft, this zone is above the inversion where the air is extremely dry due to its isolation from oceanic moisture.  Several times a year major storms may deposit up to a foot of snow between Oct-May on the summit but melts because of the warmer temperatures that soon arrive after the storm.  



Haleakala volcano



Smmit of Haleakala



Kona storms are similar to cold fronts and are features of the winter storm. The rain in a well developed Kona storm is more widespread and more prolonged than in the usual cold front storm, but does not have  as strong of extreme winds as a cold front.  Kona rains can last from several hours to several days.  

On Dec 7 2007, a low pressurs system, which formed north of the Hawaiian islands caused very strong winds topping out at 50-70+ mph range, along with flooding rainfalls.  This caused property damage, downed power lines, land and mud slides and thunderstorms on all the islands, and Maui was getting the worst of it.



www.pdc.org/PDCnewswebarticles/2007/mauirainreports



Surfing is a big time activity in Maui that draws the attention of vacationers. Some of the best surfing in Maui is on the north shore, the waves can reach up to 9ft in the winter months between Nov-Feb. The reason that the northern part of Maui has bigger waves than the rest of the island is because of the wind and ocean currents that circulate through the Pacific ocean.  The N. Pacific drift is a warm current which is part of the N. Pacific Gyre that flows eastward across the N. Pacific ocean. It is a continuation of the Kuro Shio current, but doesn't extend right across the Pacific, it turns south right at about the longitude of Hawaii, which would be the northern shores of Maui.  The Subtropic Highs wind patterns are a upper air convergence and radiational cooling that causes the air to subside in the subtropics.  Subtropic Highs wind patterns are a major force behind major ocean currents.  The Westerly winds are also play a role in the ocean currents that effect the island of Maui.  The Westerly winds of the middle latitudes are winds from the west and east , bounded by jet streams and often invade the belt of the Westerlies.
Jaws is the most popular spot for big waves on Maui.  Jaws is located in Peahi, which is 3mi north of Paia. If you want to have a good time surfing surf Jaws, because there are no other waves like it on the island of Maui.


Jaws