Lihue Airport, a little more than 100 feet above sea level, is located near the eastern shore of the island of Kauai. The island is 33 miles long and 25 miles wide and has an area of 555 square miles. The eastern one-third of Kauai consists of broadly eroded valley lands, the western two-thirds is mostly mountainous. Kawaikini, the highest elevation on the island, 5,170 feet above sea level, lies near the center of Kauai and is 20 miles northwest of the airport.
The outstanding features of the climate are the equable temperatures from day to day and season to season, the persistent northeasterly trade winds and the marked variation in rainfall from the wet to the dry season and place to place.
The equable temperatures are associated with the mid-ocean location of the island and to the small seasonal variation in the amount of energy received from the sun. The range in normal temperatures from the coolest month, February, to the warmest month, August, is less than 8 degrees. The daily range in temperature is also small, less than 15 degrees. The trade winds blow across the island during most of each year and the dominance of these winds has a marked influence on the climate of the area. Completely cloudless skies are quite rare. On the average, clouds cover six tenths to seven tenths of the sky during the daylight hours.
Trade wind showers are relatively common. Although heavy at times, most of the showers are light and of short duration. The frequency and intensity of the showers increase toward the mountains to the west. Mt. Waialeale receives 486 inches annually, the highest recorded annual average in the world. Mt. Waialeale has recorded annual rainfalls in excess of 620 inches.
Normal annual rainfall is over 40 inches. Three-fourths of this total, on the average, falls during the seven month wet season which extends from October through April. Widespread rainstorms, which account for much of the precipitation, occur most frequently during this period. Normal precipitation in January, the wettest month, is over 6 inches.
The dry season includes the months of May through September. June, the driest month, receives only about 1.5 inches of rain, on average.
Hurricanes and other severe windstorms are quite rare. Strong winds do occur at times in connection with storm systems moving through the area, but seldom cause extensive damage.
Relative humidity, moderate to high in all seasons, is slightly higher in the wet season than in the dry. However, even during periods when the temperature and humidity are both high, the weather is seldom oppressive. This is due to the trade winds, which provide a system of natural ventilation during most of each year.