• 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, as well as towards the end of the dry season.
  • Largely fueled by drier soils, the onset of the Caribbean Heat Season – which is characterised by the recurrence of heatwaves – typically occurs in April or May. Nonetheless, in recent years, the onset has occurred as early as March (in Belize and Trinidad) or April (elsewhere).
  • In the Guianas, the Greater Antilles and, in some years, the Lesser Antilles, the wet season tends to start in May, with a return of heavy rainfall.
  • In addition, though the 2026 Atlantic Hurricane Season officially starts on 1 June, tropical cyclones have occurred and are increasingly common before that date, and strong activity can occur very early on in the season.
  • Severe weather systems related to tropical cyclones, as well as heavy showers may affect Caribbean territories repeatedly as early as April or 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/).
  • The frequency of Saharan dust incursions into the Caribbean tends to increase during this period to reach its annual peak which starts 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?
  • Ocean temperatures in and around the Caribbean are warmer than average and are forecast to remain so.
  • Due to these unusually warm waters in the Tropical North Atlantic Ocean, air temperatures and humidity during the transition into the Heat Season are likely to be higher than usual, but unlikely to the point of significant heat stress in March.
  • In recent months, cooler than average temperatures in the tropical Pacific Ocean, signified weak La Niña The forecast suggests a very likely return to near average temperatures there – i.e., ENSO neutral conditions – in the upcoming three-month period.
  • Years in which Caribbean Sea and (Sub-)tropical North Atlantic Ocean temperatures are high, typically drive:
    (1) an uptick in excessive, humid heat in the Caribbean to the point of significant heat stress during the Heat Season;
    (2) an early and possibly rapid transition into the wet season – this year particularly in the Lesser Antilles – with shower intensity increasing into May, thereby potentially triggering episodes of flooding and flash floods; and
    (3) potentially, an early onset of an active Atlantic Hurricane Season.
  • The timing of the start and the intensity of the wet, heat and hurricane seasons will ultimately depend on the frequency of atmospheric patterns that either are conducive to or suppress ‘deep convection’ – i.e., strong vertical updraughts of hot and mostly humid air which can trigger severe weather.
  • One well-known example of suppressive conditions is the frequency of intrusion of very dry (and, at times, dust-laden) air from the Sahara higher up in the atmosphere, the so-called ‘Saharan Air Layer’ or SAL.
  • If SAL intrusions end up more frequent than usual, the odds that 2026 will bring episodes of hot & humid conditions increase causing heat stress. Furthermore, such SAL intrusions are often accompanied with dust haze and, consequently, deteriorated air quality. In addition, any ongoing drought concerns may be prolonged, with increased wildfire potential and frequency of dry spells.
  • By contrast, more Saharan air intrusions also translate to more erratic tropical cyclone and other severe weather activity, as well as reduced potential for flooding, flash floods and associated hazards and impacts. The exact timing of these SAL intrusions is not predictable at the seasonal timescale, but weather forecasts (up to 7 days in advance) can easily pick these up. It is, therefore, recommended that stakeholders pay close attention to the local weather forecasts as it pertains to haze and dust.

• In light of the unusually warm waters around the Caribbean, the forecast for March to May 2026 further suggests:
  • The forecast for seasonal rainfall amounts over the three-month period suggests likely even lower rainfall totals than usual in Barbados, the Leeward Islands and the Windward Islands (moderate confidence). Elsewhere, the forecast presents little information on rainfall totals at this time.
  • However, relatively dry air above the Tropical North Atlantic dominated through September 2025, which had led to long-term drought in many areas – particularly in Barbados and the Windward Islands -, and exacerbated by (near-)record heat in several locations.
  • Consequently, Long-term drought is imminent in Grenada and evolving by the end of May in the ABC Islands, Dominica, Martinique and St. Vincent (high confidence) and might possibly develop or continue into the end of May in northern parts of the Dominican Republic and the islands of Saint Martin and St. Barts (medium confidence). Long-term drought (on a 12 months timescale) affects water availability across a multitude of socio-economic sectors in countries where the main freshwater resource is from very large rivers, large reservoirs or groundwater.
  • Despite the pre-existing long-term drought in multiple areas of the Caribbean, short-term drought is less of a concern by the end of May. Nevertheless, short-term drought might possibly develop or continue in northern parts of the Dominican Republic and the islands of Saint Martin and St. Barts (medium confidence). Short-term drought may impact food production, water quality and quantity from small streams, small ponds and other surface sources.
  • Night-time and day-time temperatures, as well as humidity will likely be at least as high as usual in Belize, The Bahamas, Cayman Islands, Cuba and Jamaica, with unusually warmer nights also expected for other parts of the region (medium to high confidence). Episodes of heat stress can develop as early as March in inland areas of Belize, the Guianas and Trinidad, or as early as April elsewhere.

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.