Kīhei is an area in Maui County, Hawaiʻi, United States. The population was 20,881 at the 2010 census. It is located on the leeward side of Haleakala on the South Side of Maui, . The climate is arid, receiving no more than 10 inches (250 mm) of rain per year. Several research facilities are located in Kihei, including the main offices for the Hawaiian Islands Humpback Whale National Marine Sanctuary and the Maui Research and Technology Park, which is home to the Maui High Performance Computing Center (MHPCC), and the Pacific Disaster Center and is overseen by the Air Force Maui Optical and Supercomputing observatory.