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- The Intertropical Front (ITF) continues its normal northward ascent and remains above its climatological position (Figure 1).
- Globally, the region has experienced below-average to average cumulative rainfall, with some localized areas receiving above-average amounts (Figures 2&3).
- The main season harvest in the bimodal zone is underway, and harvest is expected to be at least average.
- The Intertropical Front (ITF) continues its normal northward progression and remains north of its climatological position along its entire length. Its dekadal average position during the second dekad of August varied between 20.9°N over the western (10°W-10°E) region, or about 1.2 degrees north of its climatological position, and 18.9°N in the eastern (20°E-35°E) region, or 1.3 degrees above the long-term average position (Figure 1).
Figure 1
Source: NOAA/CPC
- Seasonal cumulative rainfall anomaly from 1 April to 20 August 2025 (Figure 2) has been below average to average over most of the region. Some localized areas show moderate to severe deficits, including in southwestern Mali, central Niger, southeastern and northwestern Chad, in the Sahelian band; and in central-western Liberia, southwestern Cote d’Ivoire, central-eastern Ghana, central-western Nigeria, southern Cameroon, and southeastern and northern parts of the Central African Republic in the Sudano-Guinean and bimodal zones. These rainfall deficits are not expected to have a negative impact on crop and pasture development in the Sahelian band, given the favorable rainfall forecast for the September–November period. These areas will be closely monitored through the end of the season.
Figure 2
Source: USGS/FEWS NET
- Figure 3 shows that across the Sahelian band, rainfall conditions remained generally favorable from 16 July to 15 August 2025, except in parts of southern Mauritania, which are experiencing moderate to severe rainfall deficits and dry spells lasting more than 11 days; in localized areas of northern and central Senegal, where there is a moderate rainfall deficit and dry spells of 8 to over 11 days; and in western, southern, and parts of central Mali, where there is a severe rainfall deficit accompanied by dry spells of less than 8 days. Moreover, the combined estimated and forecasted rainfall from 6 to 31 August 2025, indicates that significant relief is expected over the areas mentioned above (Figure 4). Also, the main season harvest in the bimodal zone is underway, and harvest is expected to be at least average.
Figure 3
Source: USGS/FEWS NET
Figure 4
Source: CHC/USCB
- Observed heavy rainfall and forecasted above-average rainfall has led to flooding in Guinea-Bissau and western Guinea, Senegal, The Gambia, and southwestern Mauritania in recent days. Flooding has also affected Bauchi, Plateau, and Niger states in Nigeria, causing widespread damage. Elevated rainfall over the past week has raised flood risk in southwestern Niger, northern Burkina Faso, and Mali. Continuous moderate rainfall since last month has caused flooding along the Logone and Chari Rivers in Chad. Flooding was reported in eastern Nigeria, along the Benue River in recent weeks and has expanded into northern Cameroon.
- Regarding desert locust outbreaks, during July 2025, adult groups have started to appear in Mauritania, with many isolated and scattered adults and some breeding observed. Isolated adults were also found in Niger and Chad.
- According to the NMME precipitation forecasts, the second rainy season from September to November is expected to be below average to average over the Gulf of Guinea. Conversely, the rainfall from September to November is expected to be average to above average over the Sahel, northern Cameroon, and the Central African Republic.
- According to the NMME-based streamflow (August–December 2025) and GloFAS streamflow (18 August–26 September 2025) forecasts, there is a high likelihood of flooding along the upstream Niger river in Mali and Niger, upstream Senegal river in Mali, Benue River in Nigeria, Logone and Chari rivers in Chad, but average conditions along downstream Niger and Komadougou rivers in Nigeria. There is uncertainty about the timing and severity given the long-range nature of the forecast.
- According to the FAO Locust Watch, there is still a possibility that adult groups will migrate from the central Sahara towards Chad, Niger, Mali, and Mauritania. Summer breeding will increase in Chad, Niger, Mali and Mauritania.
Source: FEWS NET
Recommended citation: FEWS NET. West Africa Seasonal Monitor August 29, 2025: Mixed rainfall conditions across West Africa and the Sahel, with areas of above- and below-average rainfall, 2025.
FEWS NET’s Seasonal Monitor reports are produced for Central America and the Caribbean, West Africa, East Africa, Central Asia, and Somalia every 10-to-30 days during the region’s respective rainy season(s). Seasonal Monitors report updates on weather events (e.g., rainfall patterns) and associated impacts on ground conditions (e.g., cropping conditions, pasture and water availability), as well as the short-term rainfall forecast. Find more remote sensing information here.