Because Hawaii is entirely in the tropics, the relatively pleasant climate allows for any major Activities to be carried out throughout the entire year as long as the weather permits. However, there are two distinct seasons (summer and winter) with their own distinct weather patterns. Knowledge of these patterns can empower you to better plan an Activity Hawaii vacation.
Wind and Rain Patterns:
Trade Winds: During the summer months from May through September, the winds that blow across Hawaii prevail from the northwest known as the Trade Winds and as it travels over the Pacific Ocean, it gather moisture. As the winds encounter the mountains of the islands, the moisture in the rapidly rising air mass condenses and form clouds and moderate showers along the coast. The side of the island encountering this air mass is called the Windward side of the island and tends to be cloudier during the winter months from October through April. For the islands of Kauai, Oahu, Molokai, Lanai, and west part of Maui, the air mass passes over the mountain tops and descends down the other side of the islands depleted of much of its moisture and because less clouds and light showers occur here, this side of the island is called the Leeward side. Clearly, the Leeward side of the islands have the best Activity Hawaii weather. However, the trade wind passes around the very tall east Maui (Haleakala Volcano) mountain and the two tallest mountains (Mauna Loa and Mauna Kea volcanos) on the big island. The windward coasts of east Maui and Mauna Loa volcano are very wet and at times very windy. The Kona coast (Leeward) at the base of Mauna Kea volcano receives more rainfall in the summer season than during the winter season, which is due to the Kona effect, that is, as Mauna Kea volcano heats up during the daylight hours, the warmed air surrounding the mountain top rises pulling with it the moist air along the coast of Kona resulting in cloud formation and rain. In spite of the rain, the summer season is the best time for Activity Hawaii along the Kona Coast. Kona Winds: During the winter season, the trade winds blow about 40% of the time and major storms (cold fronts, storm eddies or lows, true tropical storms, and low pressure systems) with strong winds occur much more frequently than during the summer season. Cloudy conditions are caused by the incoming trade winds on the windward coast. Storms originating in the south, which are referred to as Kona Winds, cause cloudiness on the Leeward sides of the islands, however, these clouds are usually pushed over the windward side as well. Based on the wind patterns of each season, the summer season is the best time of the year for outdoor Activity Hawaii.
Wind Speed Patterns:
During the summer season, the trade winds travel over the ocean at speeds greater than 12 miles per hour for 50% of the year. However, the protruding mountains of the larger islands serve to either speed up or slow down the prevailing winds over the land. During the winter season, the trade winds blow more than 12 miles per hour for 40% of the year and tends to be light and variable. Also, during the winter season, there can be occasional episodes of very strong winds coming in from any direction. On rare occasions, tropical storms and hurricanes move over the Hawaiian islands, but they do not occur every year. Hurricanes Della, Nina, Dot, Iwa, and Iniki passed over or near Kauai Island in September 1957, December 1957, August 1959, November 1982, and September 1992, respectively. The passing of hurricanes across Hawaii usually occur when the Pacific Ocean warms up right around Christmas time and this event is called El Nino for the Christ Child by the Peru fishermen. It is the warm Pacific waters that give the hurricanes their strength and power. During an El Nino weather period, the summer season in Hawaii is wetter than usual and the winter season is noticeably drier. In contrast, when El Nino gives way to its sister weather pattern, La Nina, the threat of hurricanes are absent and Hawaii’s weather returns back to normal, where the summer seasons are drier and the winter seasons are wetter. In spite of the wetter summer caused by an El Nino event, the summer season is the best time of the year for most outdoor Activity Hawaii.