Hawaii Weather Guide: Climate, Seasons, and What to Expect

Hawaii has warm weather year-round. Sea-level temperatures range from roughly 75°F (24°C) in winter to 88°F (31°C) at peak summer, and the ocean is always swimmable. But Hawaii is not uniformly sunny: the islands have dramatically different rainfall patterns depending on which side of the island you are on and how high the terrain rises. Understanding how weather works in Hawaii helps you choose the right base and plan activities more effectively.

Hawaii's climate basics

Hawaii sits in the tropics at roughly 20-22 degrees north latitude, close enough to the equator for warm temperatures year-round but far enough north to have distinct, if mild, seasons. The dominant weather pattern is the northeast trade winds, which blow steadily for most of the year from the northeast. These trade winds carry moisture from the ocean and drop it when they hit the mountains, creating the extreme rainfall on windward coasts and leaving the leeward coasts dry.

Average sea-level high temperatures: 80-82°F (27-28°C) in winter (January-February), rising to 87-90°F (31-32°C) at peak summer (August-September). Overnight lows stay mild: 65-72°F (18-22°C) at sea level even in winter. These temperatures are for the coast; higher elevations are significantly cooler. The summit of Haleakalā on Maui at 10,000 feet averages 40-55°F (4-13°C) and the summit of Mauna Kea on the Big Island at 14,000 feet is below freezing on many days and receives occasional snow in winter.

Wet and dry seasons

Hawaii's wetter season runs from roughly November through March. During this period the trade winds become less consistent, allowing fronts from the north to pass through more frequently. Windward coasts receive heavy rain; leeward coasts are affected less but still see more variability than in summer. The dry season runs April through October, when stable trade winds return and rainfall on windward coasts decreases substantially.

The word "rainy season" can be misleading. Even in winter, most leeward (southwest-facing) areas of each island receive minimal rainfall. The sun/rain distinction in Hawaii is mainly about which side of the island you are on, not which month it is. A visitor based in Wailea on Maui's south coast or in Kailua-Kona on the Big Island's west coast will experience excellent weather even in January and February.

Weather by island

Oahu: Honolulu averages about 17 inches of rain per year, making it one of the drier major cities in the U.S. The mountains above Honolulu (including the Koʻolau Range) receive 100+ inches annually; the rain falls on the windward side. Waikīkī is reliably sunny. The north shore is much wetter.

Maui: The south Maui coast (Kīhei, Wailea) is one of the driest in Hawaii. The east Maui coast (Hāna area) is extremely wet: Hāna averages over 90 inches of rain per year. Haleakalā summit is often in clouds. South Maui is the most reliable for sun.

Kauaʻi: The north shore and the interior (Mount Waialeale holds the world record for annual rainfall at around 450+ inches) are extremely wet. The south shore (Pōʻipū) is semi-arid and reliably sunny, making it the most dependable base for visitors who prioritize sun.

Big Island: Has the most climatic diversity of any island due to its size. The Kona coast is reliably dry and sunny. Hilo on the east coast is one of the wettest cities in the U.S., averaging over 130 inches of rain per year. The summit of Mauna Kea is above the clouds on most days.

Microclimates and leeward vs windward

The single most important weather decision for your Hawaii trip is which side of the island you base yourself on. Windward (northeast-facing) coasts receive trade wind moisture and are lush, green, and rainier. Leeward (southwest-facing) coasts are in the rain shadow of the mountains and are drier, sunnier, and hotter. Most major resort areas are on leeward coasts precisely for this reason.

Microclimates can change within a few miles. On Maui, the transition from dry Kīhei to wet Kahului is only 8 miles. On the Big Island, you can drive from the desert-like Kona coast to the rainforest near Waimea in an hour. Planning activities on the leeward side of whichever island you visit on any given day is the most reliable approach to avoiding rain. For the full month-by-month view, see best time to visit Hawaii.