• What can we usually expect during this period?
  • Climatically, March to May forms the late Dry Season in Belize and the Caribbean Islands.
  • This season is characterised by relatively few wet days and a small number of wet spells, but many dry days and quite a few dry spells.
  • The resulting drier surface and foliage increase wildfire potential and the concentration of airborne particulates. Local dust levels should also be increasing during prolonged dry spells and towards the end of the dry season.
  • In the Guianas, the Greater Antilles and, in many years, the Leeward Islands, the wet season tends to start in May, with a return of heavy rainfall.
  • Coincidentally, largely fueled by drier soils, the Caribbean Heat Season – characterised by the recurrence of heatwaves – commences in April (in Belize, Cuba, Trinidad) or May (elsewhere except for the Guianas).
  • In addition, though the 2023 Hurricane Season officially starts on 1 June, tropical cyclones have occurred and are increasingly common before that date.
  • The frequency of Saharan dust incursions into the Caribbean tends to increase during this period to peak starting in May. It should be noted that, in some years, significant Saharan dust episodes also occur in March and April. (Access more detailed forecast information on dust and air quality in the Caribbean may be found here: http://dafc.cimh.edu.bb/).
  • UV exposure is set to be dangerously elevated. On a scale from 1 to 12, the UV index on sunny days will be 8-10 (very high) to 11-12 (extremely high).

• What is different this year?
  • A moderate La Niña event in the Pacific Ocean had started in September 2020 and appears to be coming to an end this month.
  • The Pacific is transitioning into ENSO neutral. This means that both the Eastern Tropical Pacific Ocean and North Atlantic Ocean temperatures – and, thereby the Caribbean – are expected to be close to average.
  • This change makes it difficult to forecast unusual climate conditions in the Caribbean this late dry season.
  • However, in case the Pacific transitions into El Niño by May, then chances of drought, weaker tropical cyclone activity, but more frequent heatwaves increase.

• In light of this year’s changing ocean conditions, the forecast for March to May 2023 suggests:
  • A faster depletion of water reservoirs than usual for the late dry season in Cuba in view of a reduced number of wet spells. Wildfire potential and local airborne dust will be increasing until heavy rains return in view of a low frequency of wet days (medium confidence).
  • Flash flood and long-term flooding potential arising from excessive rainfall will be slight (i.e., occurs once every 5-10 years) for most areas in March but — with the exception of the ABC Islands — will increase to moderate (i.e., occurs at least once every 5 years) or high (i.e., occurs at least once every other year) into May. Persons should keenly monitor weather advisories issued by the National Meteorological Services and other information provided by the Caribbean Disaster Emergency Management Agency (http://cdema.org/) and the US National Hurricane Center (https://www.nhc.noaa.gov/).
  • Short-term drought (on a 3-6 months timescale) concerns arise in the Northern Bahamas, Barbados, Western Cuba, Dominica, Dominican Republic, Martinique, Puerto Rico, St. Barts, Sint Maarten/St-Martin, St. Vincent, and the USVI, where drought is possible by the end of March (medium confidence). Long-term drought (on a 12 months timescale), which may affect water availability across a multitude of socio-economic sectors in a country, is evolving in Central and Western Cuba (high confidence), and may possibly develop or continue in Eastern Cuba, southern Dominican Republic and St. Vincent (medium confidence).
  • Heat discomfort should not be a significant concern through March. However, heatwaves do occur in April, especially in Belize and Trinidad, and in areas in drought (Cuba), and in May across the Antilles. (high confidence).

This Bulletin provides a broad overview of climate conditions up to 3 months in advance. It is based on insights drawn from CIMH’s suite of technical climate information products and epidemiological insights from CARPHA and PAHO. The information contained herein is provided with the understanding that the CARPHA, the PAHO and the CIMH make no warranties, either expressed or implied, concerning the accuracy, completeness, reliability or suitability of said information. The Bulletin may be freely used and disseminated by the public with appropriate acknowledgement of its source but shall not be modified in content and then presented as original material.