Kwajalein Climate Summary

Kwajalein Climate Summary

For detailed climatological surface data, see the Surface Data section or any of the following: 
Daily Normals           
Monthly Precipitation
Monthly Average Temperatures
Monthly Normals/Means/Extremes

Summary
Kwajalein’s location gives it a tropical marine climate characterized by two main seasons, a wet season and a dry season, with little temperature variation between them. The atoll experiences the dry season typically from mid-December to mid-May dominated by brisk east-northeasterly Trade Winds, and the wet season from mid-May to mid-December where winds tend to be lighter and of more variable direction. Normal annual rainfall is approximately 100 inches; approximately 72% of which occurs during the wet season. A pronounced diurnal cycle is present, with two thirds of atoll rainfall typically recorded between midnight and sunrise.  On average, the prevailing wind direction is from the east-northeast during the entire year, although, winds may become more variable, especially during the wet season, when occasional southerly or even westerly winds occur. Average wind speed is near 17 mph in the dry season and near 12 mph during the wet season. Although thunderstorms do occur, most of the precipitation at Kwajalein comes from rain showers.

The average daily maximum temperature is 86.5°F (30.3^oC); the average minimum is 77.6°F (25.3^oC). Average relative humidity ranges from 78% at local noon to 83% at midnight.

Weather Summary Table

* Significant west-wind and west-swell events are more likely to occur in strong El Nino years.
** Averages can be misleading. The tropical climate normally produces long wet or dry periods. On small tropical islands, without mountain effects, about 2/3 of annual rainfall occurs between midnight and sunrise.
*** Shows probability of experiencing at least a few drops of rain (trace or more) anytime in the 24-hour day.
**** Many high clouds are generated from deep tropical convection patterns. These high clouds frequently spread into our area. Average cloud cover statistics include contributions from thin/translucent high clouds that are not always visible from the ground.

Tropical Storm Activity
Kwajalein is on the eastern edge of the Western Pacific typhoon generation zone, an area where tropical depressions frequently form.  During the modern era of record keeping, since 1919, a fully developed typhoon eye has never made direct landfall on Kwajalein Atoll. However, tropical storms have had significant impacts upon Kwajalein's atoll with sustained winds ranging from 25-52 mph. The table below details several notable tropical storms that have approached the atoll.