The state of Hawaii is made up of an island chain that extends for about 2,600 km (about 1,600 mi) between the island of Hawaii in the southeast and Kure Island in the northwest. The state has a total area of 16,729 sq km (6,459 sq mi), including 93 sq km (36 sq mi) of inland water.

The islands of Hawaii have a number of short streams and a few small ponds, but there are no large lakes. Among the longest rivers, none of which is more than 50 km (30 mi) long, are the Wailua and Waimea rivers, on Kauai, the Wailuku River, on Hawaii, and Kaukonahua Stream, on Oahu. Koloa Reservoir, a body of water that covers 171 hectares (422 acres) on Kauai, is the largest inland lake. Waterfalls abound on most of the main islands.

The eight main islands of Hawaii, which lie just south of the tropic of Cancer, have a tropical climate that is determined by their latitude and oceanic setting and by the influence of the prevailing northeast trade winds.

Average temperatures range between 22° and 26° C (72° and 79° F) throughout the year at low elevations. Lowland temperatures vary only a few degrees from month to month and rarely more than 6° C (10° F) from day to day. Extreme temperatures rarely occur. Daytime temperatures hardly ever rise above 35° C (95° F), and temperatures below freezing are practically unknown at elevations of less than 1,200 m (4,000 ft). Weather conditions above about 2,500 m (about 8,200 ft) can be quite severe, especially during the winter months