[GCBDKT4] The "Maui Air Conditioner": Trade Winds of Kihei
At these coordinates, you can observe the direct geological and climatological impact of Maui's famous trade winds. Kihei is situated on the island's leeward side, where a powerful and consistent atmospheric phenomenon shapes the daily weather, landscape, and even local culture. By completing the logging tasks, you will learn how the massive Haleakalā volcano and the principles of global atmospheric circulation interact to create Kihei's famously warm, dry, and breezy conditions.
Understanding trade winds
The engine behind the trade winds is the solar heating of the Earth. Near the equator, the sun's direct heat warms the air and causes it to rise. This rising, warm, and moist air creates a persistent low-pressure zone called the Intertropical Convergence Zone (ITCZ) or "the doldrums". At approximately 30 degrees north and south of the equator, the air that rose at the ITCZ has cooled, becoming denser, and begins to sink. This creates a high-pressure zone and a constant cycle of air movement known as the Hadley Cell.
The trade winds are the surface-level winds that flow from these high-pressure zones back toward the low-pressure equator. In the Northern Hemisphere, the Earth's rotation adds another layer of complexity. Due to the Coriolis effect, the air moving south from the North Pacific high-pressure system is deflected to the right, causing it to blow from the northeast.
Why Kihei is different
As these northeast trade winds travel across the Pacific, they pick up immense amounts of moisture. When they hit the north and east coasts of Maui, they are forced upward by the towering slopes of Haleakalā and the West Maui Mountains. This uplift causes the moist air to cool, condense, and fall as rain. The result is a lush, green, and wet "windward" side of the island.
By the time the trades descend the leeward (southwest) side of the mountains, they have lost most of their moisture and become warm and dry. This is why Kihei and other leeward communities experience a drier, sunnier, and more desert-like climate compared to the rest of the island. The mountains also create a venturi effect through the valley connecting Haleakalā and the West Maui Mountains, funneling and accelerating the trade winds directly towards Maʻalaea and north Kihei.
The trade winds are so central to Kihei's identity that they are often called "the Maui air conditioner," providing a welcome breeze on warm days. The intensity of these winds can vary throughout the day, often starting calm in the morning and building in the afternoon, making mornings ideal for swimming and afternoons perfect for windsurfing.
Logging tasks
To claim this EarthCache, you must visit the coordinates and perform the following tasks. Please message your answers to the cache owner and and log your find.
- Observe the wind. At the posted coordinates, what is the wind doing? Describe the direction the wind is blowing relative to the coastline? Based upon the time of day, do you expect the wind to increase or decrease as the day goes on? Why?
- Observe the clouds. Look toward the slopes of Haleakalā to the east. Observe the cloud cover. Based on what you learned, why do you think there is more cloud cover over the mountain than over Kihei? (Note: If cloud cover in Kihei prevents you from seeing the slopes of Haleakala, the same effect can be seen looking at clouds over west Maui.)
- Compare climates. Standing at the viewing area, you can look out across the island. Based on your experience and the cache description, explain why the climate you are experiencing in Kihei is significantly different from the weather on the other side of Haleakalā or east side of west Maui.
Post a photo of yourself and your GPS or Personal item at the coordinates with the ocean and mountains in the background. Please include photo with your log.
Additional Sources:
Lets Talk About Maui Trade Winds
A Guide to Understanding Mau's Weather - Hawaii Ocean Projects
This Earthcache was written with the help of Google built-in AI.