So. Weather on Maui as it directly effects the tours and activities you might take, is determined by a number of factors: wind, rain, temperature and ocean conditions. If you understand how they relate to one another you will best be able to plan for and enjoy your activities while on vacation.
Wind
So, Bob Dylan’s famous song line “It doesn’t take a weather man to know which way the wind blows”, is very apt here on the island. If you know which way the wind is blowing you will have a great idea regarding how the weather will be in the area of the island you are planning to visit.
Fortunately Maui makes things easy for use on most days because about 250-300 days out of the year the Trade Winds will blow. These winds blow out of the northeast and predominantly hit our northern and eastern shoreline. When this happens we will likely have a stiff, clean breeze averaging 10 – 30 miles per hour on the northern shores and calm gentle breezes on the protected southern coastlines such as in Lahaina or Kihei. These winds will usually have a ‘wrap around’ effect as the day goes on and so they will eventually produce winds in the late morning or early afternoons on much of the leeward coasts. Because Maui is an island consisting of two large mountains, Haleakala and the West Maui Mountains, as the Trade Winds try to navigate around these two large land masses they will meet in the middle and their speed will increase do to the funnel effect as they join forces. It is for this reason that we generally recommend taking your snorkel trip to Molokini in the mornings rather than afternoon as the winds, if any, won’t be anyway near as strong.
Trade Winds will generally be with us in the spring, summer and autumn months and these are generally the most favorable conditions of the year.
In the winter months the ‘wind can blow backwards’, or come from the south in what we refer to as ‘Kona Winds’. These winds do not happen in anywhere near the frequency of the ‘Trades’ but when they do occur they will hit the island on the south side and then northern coastlines will be still. This is also the time of year we can have our ‘Kona Storms’ and these will bring rain (sometimes very heavy) to the south side of the island and will definitely effect almost all of our boat tours, luaus and whatever else is located on our south and west coastlines. A strong Kona Storm can cause inclement weather for a week at a time, but keep in mind that the north side of the island might be quite nice.
Regarding the winds, the one aberration that can occasionally occur, usually in September but also its surrounding months, are the hurricanes. Infrequent as they may be, even the hint of the possibility of one occurring will cause the tour and activity industry to button up and shut down until it passes.
Rain
Rain is also somewhat a function of the wind as well and the severe rain will generally fall in the winter seasons though some precipitation is experienced on the island every month of the year. Because each portion of the island is considered a ‘micro climate’ the rainfall will vary somewhat throughout the year depending upon where you are staying. Here is a brief rundown of rainfall for three different parts of the island where you might be staying.
If you will be staying in Lahaina during the winter season (November through March) you can expect between 3.5″ to 1.8″ a month and in the summer season (April through October) you could expect between 1.1″ and .1″ of rainfall.
If you are staying in Kihei during the winter season (November through March) you can expect between 4.1″ and 2.6″ per month and in the summer season (April through October) you could expect between 1.8″ and .3″ of rainfall.
If you are staying in Hana during this winter season (November through March) you can expect between 8.52″ and 5.69″ a month and in the summer season (April through October) you can expect between 7.46″ and 4.10″ of monthly rainfall.
Temperature
Maui is very agreeable all year long with regard to temperatures. It is almost always comfortable here. Once again here are the same three areas of the island with the average temperatures for both winter and summer.
If you are staying in Lahaina your average high temperature during the winter would be between 81 – 85 degrees F. and your average low temperature would be between 64 – 68 degrees F.
In the summer your average high temperature would be between 84 – 88 degrees F and your average low temperature would be between 65 – 68 degrees,
If you are staying in Kihei your average high temperature during the winter would be between 81 and 84 degrees F. and your average low temperature would be between 64 and 67 degrees F. In the summer your average high temperature would be between 82 and 87 degrees F and your average low temperature would be between 66 and 70 degrees F.
If you are staying in Hana your average high temperature during the winter would be between 79 – 81 degrees F. and your average low temperature would be between 63 – 65 degrees F. In the summer your average high temperature would be between 80 – 84 degrees F and your average low temperature would be between 63 – 68 degrees F.
Ocean Conditions
The ocean conditions on Maui also vary between summer and winter months. During the summer months the swells hit along Maui’s south shores and during the winter the hit along our north shoreline. The summer south swell is usually moderate and quite suitable for learning to surf but the north shore winter swell can be giant (our surf spot called ‘Jaws’ only breaks in the winter time and it can get as high as 50′ plus).
As far as ocean temperature is concerned, these are temperate throughout the whole year as well. The average winter temp is 77 degrees F. and the average summer temp is 82 degrees F.
The other factor you should be aware of regarding ocean conditions during all times of year is that the ocean water is generally calm in the mornings and in the late morning and afternoons it gets windy. It then usually dies down again in the late afternoon and evening.