Let’s start with a quick geography lesson.

All Hawaiian islands share geographic features that impact the climate across the islands. The islands were formed by volcanos, giving them tall mountains in the interior that stretch into plains along the shores. In fact, the tallest mountain in the world (from base to summit) is Mauna Kea on the Big Island. The trade winds blowing in off the ocean create predictable weather patterns across the islands due to the mountainous interiors. As the winds blow in and over the mountains, the air cools and water vapor condenses and falls as rain showers. This side of the island is known as the windward side. On the other side of the mountains, the winds lose their moisture, creating drier conditions with less rainfall. This side of the island is the leeward side. You can easily recognize which side of the island you’re on. The wetter, windward side will be lusher, greener, and more tropical, while the drier leeward side will look more like the grassy plains of the midwest or even deserts. In fact, don’t be surprised to see cacti along the leeward sides of islands in Hawai’i.

The windward side of the islands is typically along the northern and eastern coasts. On Maui, for example, the windward side is predominantly along the eastern shore, creating the tropical conditions you’ll find on the road to Hana. West and south Maui, while known for its beautiful beaches, is much drier with less vegetation.