Long-range Weather Forecast

Hawaii

Annual Weather Summary
November 2008 to October 2009

Detailed 2009 Long-Range Forecast
for the Hawaii Region

Includes predictions for all or portions of Hawaii (Hilo, Honolulu, Kahului, Pearl City, Waipahu).

Winter will be about one-half degree above normal, on average, with the coolest periods in early December and early January. Winter will be much drier than normal on Kauai and drier than normal on Oahu. Expect near-normal rainfall on Molokai, Lanai, and Maui and above-normal rainfall on the Big Island, especially in February. The rainiest periods will occur in early January, mid- and late February, and in mid-March.

April and May will be slightly cooler than normal from Kauai to Maui, with near-normal temperatures, on average, on the Big Island. May will be especially rainy on the Big Island. Elsewhere, rainfall will be below normal..

Summer will be about a degree cooler than normal, on average, with the hottest period in mid- to late August. Rainfall will be below normal, with the rainiest periods in mid-July.

September and October will each be about two degrees cooler than normal, on average, despite a warm spell in mid-September. Rainfall will be near normal, with the rainiest periods in the second half of October.

NOTE: Temperature variations in Hawaii are largely elevation-based, with higher elevations noticeably cooler than elevations closer to sea level. Precipitation often varies tremendously throughout the islands, even at similar elevations. For example, Hilo, at an elevation of 31 feet above sea level, averages more than 130 inches of rain per year, while Honolulu, at an elevation of 7 feet, averages only about 20 inches of rain per year. Because there is so much variation in rainfall, we have based the forecast on the Honolulu-Waikiki area and expressed only general trends elsewhere throughout the islands. Thus, for example, the forecast does note a widespread rain but not a locally heavy rainfall.

Detailed Forecast for the Next Two Months

Temperature and Precipitation
November 2008 to October 2009