Is it possible to have perfect weather all the time?

Well, Maui comes close, but even paradise has it's flaws. Maui is located at  20.80° N, 156.33° W, amidst the climate zone the tropic of cancer and the northern temperate zone, resulting in fairly consistent temperatures year-round with warm summers and mild “winters”. 

Summer spans from May to September with average highs in the mid-80's and peaking in the high-80's during August and September. “Winter”, or rather the rainy season, begins in October and stretches to April with average high temperatures in the low-80's, however temperatures have been know to fall into the low-60's.

Clouds generally form on the eastern side of the island, and due to that pesky little volcano in the middle of the island adiabatic processes come into play. Orographic lifting occurs where these clouds and warm air masses are forced upslope over Haleakala. As this warm moist air changes elevation and reaches the condensation point, precipitation occurs. As the clouds lose their moisture and dissipate, the dry air descends down the opposite (leeward) side of the mountain and a rain shadow forms, thus cities on the west coast such as Lahaina, Wailea, and Kihei (Kihei holla!) tend to be sunny and dry.

Maui's location leaves the weather heavily influenced by the trade winds, which are easterly winds that occur in the tropics as warm air 'rises' towards the poles, cooling, and subsequently “sinking” back towards equator to be heated again. Average humidity or amount of moisture held in the air in Maui hovers around 70%, peaking in the morning. Rainfall plays a large role in Maui's climate as a whole, and tends to happen frequently but not usually for an extended period of time per storm. Rain is most likely to occur in the morning, and most often during the winter months, or the rainy season. Severe storms, particularly thunderstorms are rare as precipitation is not usually the result of frontal or convergent lifting. 

Annual rainfall averages vary depending on where and at what elevation you are at on the island. Eastern and higher elevation areas such as Hana generally see about 85” of rain per year, exorbitant compared to lower and western regions like Kihei (Kihei holla!) that collect on average only about 8” annually. This past year however, the western/leeward side of the island saw less rainfall than usual, causing a draught. Severe hurricanes rarely hit Maui as the mountainous terrain causes the most sever typhoons to vitiate into tropical storms, yet tsunamis as a result of seismic activity in other areas of the pacific rim are a major concern, and their potential for devastation is monitored closely by the Pacific Tsunami Warning Center.