Haïti, climat et météo mensuels, août 2026

FAMINE EARLY WARNING SYSTEMS NETWORK Haiti Monthly Climate and Weather 10 September 2026 Highlights • According to the El Niño Southern Oscillation (ENSO) outlooks, El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27. • During August 2026, Haiti experienced below-average rainfall conditions. Severe rainfall deficits of 100 mm to 200 mm were observed in most of Artibonite and Centre departments. • In August, most of Haiti observed above-average maximum temperatures, with positive anomalies ranging from 1°C to 2°C above the mean. Regarding minimum temperature, southwestern Haiti experienced positive anomalies between 1°C and 2°C above the mean, while the rest of the country experienced near-average minimum temperatures. • During October – December 2026 season, the seasonal NMME probabilistic forecast indicate the continuation of below-normal rainfall conditions over Haiti. Moderate probabilities (40–60%) for below-normal rainfall are predicted in most of the country. In terms of temperatures, the NMME forecast indicates high probabilities (60% to more than 70%) above-normal mean temperatures in western, northern and southern regions of Haiti. • For August, the SPI analysis indicates severe moisture deficits in southeastern Artibonite, Nord-Est, southeastern Nord, western Nippes, eastern Grande-Anse and central Sud departments, with SPI values ranging from 1.3 to 1.6 standard deviations below the mean. The SPI forecast suggests that drier-than-average conditions (SPI values ranging from 0.8 to -1.3 standard deviations) will continue in most of Haiti. The FEWS NET Monthly Climate and Weather information bulletin is based on current weather and climate information and monthly and seasonal outlooks from the NOAA CPC. Information on crops, soil moisture, flooding, and evapotranspiration data were produced by FEWS NET, USGS, NASA and USDA. Various sources were used to assess impacts of extreme conditions. Questions or comments about this product may be directed to Dr. Wassila Thiaw, Deputy Director, CPC/NOAA, wassila.thiaw@noaa.gov. Questions about the DOS FEWS NET may be directed to Dr. Kiersten Johnson, Program Manager FEWS NET/DOS, johnsonkb2@state.gov. Haiti seasonal calendar. Source: FEWS NET Current Climate Modes and Teleconnections • • The ENSO outlooks indicate that El Niño strengthened over the past month, with sea surface temperature (SST) anomalies exceeding +3.0 °C. Collectively, the coupled oceanatmosphere system reflected a strengthening El Niño. Additionally, El Niño will continue to strengthen through the end of the year (Fig. 1), and there is a 75% chance of a historic event that would exceed the strength of previous El Niño events dating back to 1950 (+2.5 °C or more for a 3-month Relative Oceanic Niño Index) during the October-December 2026 season. For the latest update from the NOAA Climate Prediction Center (CPC) on ENSO, check here. During August 2026, SSTs were warmer than average across the equatorial Eastern Pacific Ocean, where positive anomalies ranged from 1.0°C to more than 3°C. In addition, SSTs in the eastern and western Gulf of America, the northern Caribbean Sea, and the subtropical Atlantic Ocean were above average, with positive anomalies ranging from 0.5°C to 2.0°C. Figure 1. Official ENSO probabilities for the Niño 3.4 relative SST index (5oN−5oS, 170oW−120oW) minus tropical mean (20oN−20oS). Figure updated 13 August 2026. Source: NOAA/CPC • Implications of ENSO conditions: Based on historical records, during El Niño events, drier than average conditions are likely for September to November (SON) season in most of Haiti (Fig. A1, left panel), while historical El Niño teleconnections indicate warmer than average conditions in eastern and southern portions of Haiti (Fig. A1, right panel). 2 Extreme Events • •

Most of Haiti experienced below-average rainfall and above-average temperatures. These conditions have caused a degradation in vegetation, affecting the harvest season in some regions. There was no report of fire activity in Haiti during August 2026. Rainfall/Precipitation • Climatologically, August is the second month of the second rainy season of Haiti. During this month, rainfall totals range from 100 mm to 300 mm in central and northern potions of Haiti. Total rainfall values between 25 mm and 100 mm are climatologically observed in the northwestern, portions of northeastern, and southern Haiti. Past 3 months (June – August 2026): • Totals: Over the three-month period, the largest rainfall totals ranged from 100 mm to 200 mm in eastern Artibonite, Centre, southern Nord, southern Nord-Est, and northern Ouest departments. Southern departments as well as northern departments, including Nord-Ouest, northwestern Artibonite, most of Nord, and most part of Nord-Est, received lower cumulative rainfall totals ranging from 10 mm to 100 mm (Fig. 2a). • Anomalies: Over the last three months, widespread negative precipitation anomalies dominated Haiti. The largest cumulative deficits of 300 mm to 500 mm were concentrated in most of Artibonite, Centre, southern Nord, southern Nord-Est, northern Ouest departments. Elsewhere, negative anomalies from 100 mm to 200 mm were observed (Fig. 2b). Figure 2. Satellite estimates of precipitation (CMORPH) for June – August 2026: (a) 3-month total accumulation and (b) 3-month anomaly. (c) NMME seasonal rainfall probabilistic forecast for September – December 2026. Source: NOAA/NCEP Past 1 Month (August 2026): • Totals: During August 2026, the highest accumulations ranging from 25 mm to 100 mm were concentrated in central and southeastern portions of Haiti including Artibonite, 3 Centre, southern Nord, southern Nord-Est and Ouest departments. On the contrary, the lowest totals of 2 mm to 25 mm were observed in northern Haiti as well as eastern and central Grande-Anse, western Nippes, Sud, southwestern and eastern Sud-Est departments (Fig. 3a). • Anomalies: Haiti experienced below-average conditions in August. Severe rainfall deficits of 100 mm to 200 mm were observed in most of Artibonite and Centre departments. Moderate to substantial rainfall deficits ranging from 10 mm to 100 mm were registered across the rest of the country (Fig. 3b). Figure 3. Satellite estimates of precipitation (CMORPH) for August 2026: (a) 1-month total accumulation and (b) 1-month anomaly. (c) NMME monthly rainfall probabilistic forecast for September 2026. Source: NOAA/NCEP Monthly and Seasonal Forecasts (October 2026 and October – December 2026): • Monthly: The North American Multi-Model Ensemble (NMME) models indicate there is a 40% to 60% likelihood for below-normal rainfall over Haiti during October (Fig. 3c). • Seasonal: The seasonal NMME probabilistic forecast for the October – December 2026 season indicates below-normal rainfall across Haiti. Moderate probabilities (40–50%) for below-normal rainfall are predicted in central Haiti, while higher probabilities (50-70%) are predicted in southern Haiti. Probabilities for below-normal precipitation are low (36% and 40%) in northwestern Haiti (Fig. 2c). Temperature Past 3 months (June – August 2026): • Maximums: Seasonal maximum temperatures across most of Haiti ranged from 30°C to 35°C (not shown). Regarding anomalies, positive anomalies, ranging from 1°C to 2°C above the mean, were observed in Centre, Artibonite, Nord, Nord-Est, eastern NordOuest, eastern and southern Ouest, Sud-Est, southeastern Nippes, and eastern Sud departments (Fig. 4a). 4 •

Minimums: Seasonal minimum temperatures in most of northern and eastern Haiti were between 20°C to 25°C. Lower values, ranging from 15°C to 20°C, were observed in southeastern regions of Haiti, while northwestern Haiti experienced higher values ranging from 25°C to 30°C (not shown). The country observed near-average minimum temperatures during June – August season (Fig. 4b). Figure 4. Spatial structure of temperature for June – August 2026: (a) maximum temperature anomaly and (b) minimum temperature anomaly. (c) NMME probabilistic forecast of seasonal 2-m temperature for October – December 2026. Source: NOAA/NCEP Past 1 Month (August 2026): • Maximums: Mean maximum temperatures across most of the Haiti ranged from 30°C to 35°C (not shown). Most of the Haiti observed above-average maximum temperatures, with anomalies ranging from 1°C to 2°C above the mean (Fig. 5a). • Minimums: Mean minimum temperatures across most of the Haiti ranged from 20°C to 25°C (not shown). In terms of anomalies, Nippes and eastern Sud departments experienced positive anomalies ranging from 1°C to 2°C above the mean. The rest of the country experienced near-average minimum temperatures during August (Fig. 5b). 5 Figure 5. Spatial structure of temperature for August 2026: (a) maximum temperature anomaly and (b) minimum temperature anomaly. (c) NMME probabilistic forecast of monthly 2-m temperature for October 2026. Source: NOAA/NCEP Monthly and Seasonal Forecasts (October 2026 and October – November 2026): • Monthly: The NMME forecast for October indicates high probabilities (60% –70%) for above-normal mean temperatures in southern Ouest and eastern Sud-Est departments. Notably, a higher likelihood (more than 70%) for above-normal conditions is predicted in Nord-Ouest, northern Nord, northern Nord-Est, western portions of Artibonite departments as well as along the coastal Grande-Anse, Nippes, Sud, western Sud-Est and southwestern Ouest departments (Fig. 5c). • Seasonal: The seasonal NMME probabilistic forecast for October – December 2026 indicates high probabilities (60% to more than 70%) for above-normal mean temperatures in northern, western and southern regions of Haiti (Fig. 4c). Drought and Dryness The Standardized Precipitation Index (SPI) is used to characterize meteorological drought. SPI compares the precipitation over a specific period of time with the climatology from that same period. Therefore, the SPI values can be thought of as the number of standard deviations the observed anomaly deviates from the climatology. The 1-month SPI values are a good representation of the monthly precipitation anomaly as well as the soil moisture and vegetation health. The 3-month SPI values are a good representation of seasonal precipitation anomalies. The Standardized Precipitation Evapotranspiration Index (SPEI) is similar to the SPI, but it also takes evapotranspiration into account (and therefore the impact of temperatures on water demand). Past 3 Months (June – August 2026): • Dry conditions developed over Haiti during the June – August season due to low rainfall amounts observed during these months. Standardized Precipitation Index (SPI3) values between -0.8 and -1.3 standard deviations were observed in southern Centre, central and 6 eastern Ouest, and Sud-Est departments. Notably, higher moisture deficits with SPI3 values ranging from 1.3 to 2 standard deviations below the mean were registered in rest of the country (Fig. 6a). Past 1 Month (August 2026): • For August, the SPI analysis indicates severe moisture deficits in southeastern Artibonite, Nord-Est, southeastern Nord, western Nippes, eastern Grande-Anse and central Sud departments, with SPI values ranging from 1.3 to 1.6 standard deviations below the mean. Most of the eastern, central and southern regions of Haiti observed negative SPI values ranging from -0.5 to -1.3 standard deviations (Fig. 6b). Current/Forecast (9 September 2026 – 6 October 2026): •

The SPI forecast suggests that drier-than-average conditions (SPI values ranging from 0.5 to 1.3 standard deviations below the mean) will continue in southern and centralwestern Haiti. The highest moisture deficits, with SPI values of 0.8 to 1.3 standard deviations below the mean, are expected in northwestern and southwestern Ouest, Nippes, eastern Grand-Anse department and eastern Gonâve Island (Fig. 6c). Figure 6: Spatial structure of the Standardized Precipitation Index (SPI) for (a) May – August 2026, (b) August 2026, and (c) Spatial structure of SPI constructed from observations for 10 June to 10 August 2026 and 4 weeks forecast ending on 7 October 2026. Source: NOAA/NCEP Water Requirement Satisfaction Index (WRSI) • USGS/EROS crop WRSI: The last WRSI extended product available for the 3rd Dekad of August 2026 indicates mostly ‘Average’ crop conditions in Centre, northern Nord, southern Nord-Est, southwestern Ouest, western Nippes, north-central Sud and eastern areas of Grande-Anse departments. However, ‘Failure’ to ‘Poor’ crop conditions are indicated in Nord-Est, central-western Artibonite, northern Ouest departments as well as in other isolated places in southern regions. Elsewhere, WRSI mostly shown ‘Mediocre’’ crop conditions. 7 GEOGLAM Crop Monitor • According to the August 2026 GEOGLAM Global Crop Monitor report, rice fields are under favorable conditions and maize crops are under watch conditions. The maize harvesting of Printemps season is concluding, while the harvest of the main-season rice is continuing. Additional Resources - https://protectioncivile.gouv.ht/ - https://www.meteo-haiti.gouv.ht/ Annex Figure A1. ENSO teleconnection for the September – November (SON) season. El Niño-3.4 composites for precipitation anomaly (mm/day; left panel) and temperature anomaly (°C; right panel), based on MSWEP precipitation and CORe temperature data sets, respectively. Period is 1982-2025. 8