Aruba, Bonaire and Curaçao are located in the southern fringes of the hurricane belt, not outside of it as some may say, located in the southern Caribbean dry zone. The weather is defined as being in a tropical steppe, semiarid hot climate with a discernible dry and rainy season, and having sustained moderate to fresh easterlies.
Aruba's dry season runs roughly from February through June, and the rainy season starts in September and ends in January. Rain showers occur more often in the early morning hours, and during our rainy season it can be in the early morning or early to late evening hours. The lowest average cloud cover is in the month of February and the highest average cloud cover is in the month of May, mainly due to upper-level clouds. On daily basis the average cloudiness of the sky is the highest in the morning hours and the lowest in the late evening.
Aruba's island history shows that only every 100 years there has been considerable damage done by tropical cyclones passing over or just south of the islands. Although the hurricane experience level for the islands may be regarded as nil, well known is the minor hurricane which passed just south of Curaçao on September 23, 1877 causing an estimated structural damage of US$ 2 million, mainly to the coastal section of Willemstad. A nunnery was completely washed away (remnants still visible with low tide), many ships were lost and at least 70 persons drowned. The lowest barometer reading at Willemstad was observed at 23/15:30 UTC with 995.4 millibars. A ship sailing south of Curaçao reported a lowest pressure of 988.8 millibars.
In this context the most significant events in the past few years were related to tropical storms Joan in 1988, tropical storm Bret in 1993 and tropical storm Cesar in 1996. Tropical storm Joan, which past just south of the islands on October 16, 1988, caused an estimated structural damage of approximately US$1.5 million, mainly by blown off roofs and by rough seas pounding exposed harbor and beach facilities.
On the average, once every 4 years a tropical cyclone occurs within a radius of 100 miles, but mostly passing to the north of the islands without causing serious bad weather.