The Cayman Islands built up a rainfall deficit of 6.21 inches over an 18‑month period, according to data provided by the National Weather Service.
Measurements taken from January 2018 to June 2019 show Grand Cayman has fallen below the 30‑year rainfall average for 11 of the past 18 months. That brings Cayman 8% below the 30‑year average of 74.47 inches for an 18‑month period.
The cumulative rainfall over that time span was 68.26 inches.
For 14 of those months, at least one third of the total monthly rainfall came in one day. During five of those months, more than half of the total rainfall came in one day.
The wettest single day over the past 18 months was 21 May 2018 with 3.84 inches, followed by 9 Sept. 2018 with 3.41 inches and 6 Jan. 2019 with 3.33 inches.
In the long term, the Cayman Islands can expect shorter but heavier rain events, explained Winston Gall, a Cayman Islands National Weather Service forecaster. He described the projection as an anticipated effect of climate change.
Such events are not expected to resolve rainfall deficits, however.
Overall, the Caribbean can expect a general drying of the region, explained Colorado-based climate scientist Jhordanne J. Jones, an alumnus of the University of the West Indies at Mona’s Climate Studies Group.
While 18 months of data cannot speak to larger trends, Jones said climate research indicates, “We’ll definitely get fewer rainfall events, since there’s a projected drying of the Caribbean in general.”
With warming sea and land temperatures, she said, the heat will provide fuel and intensity to the rain events that do occur.