Sahel Ends Its Rains With Dry Spells Past 11 Days, FEWS NET Reports

West Africa's 2026 rainy season is winding down with localized but persistent rainfall shortfalls across the northern Sahel, according to the latest West Africa Seasonal Monitor published by FEWS NET's agroclimatology team. The agency reports that accumulated deficits have cut into vegetation conditions and crop water availability, and that late-season rain is unlikely to make up the gap.

A front that lingered north

FEWS NET tracks the Intertropical Front (ITF), the boundary whose seasonal march north and south governs the timing of Sahelian rains. The agency says the ITF reached its northernmost position in the second dekad of August and has since retreated unevenly, leaving it north of its climatological mean along its entire length.

For the 11–20 September dekad, FEWS NET places the ITF at roughly 18.8°N in the western sector — about 0.9° north of both its climatological position and its location in the previous dekad — and at roughly 15.8°N in the east, 0.3° north of the long-term average and 0.4° north of the previous dekad.

Where the rain did not fall

Over the season as a whole, from 1 May to 20 September, FEWS NET reports cumulative rainfall deficits across parts of western Mauritania, central and northeastern Mali, northern Burkina Faso, western and eastern Niger, southwestern, northwestern and northeastern Nigeria, and much of Chad. The agency attributes below-average vegetation conditions and reduced crop water availability to those shortfalls.

The shorter window from 21 August to 20 September showed moderate-to-severe deficits combined with long runs of dry days. FEWS NET identifies western Mauritania, northern Senegal, central and eastern Mali, northeastern Nigeria and northwestern Chad as the most severely affected, with several areas recording dry spells of more than eight consecutive days. Spells longer than 11 consecutive days were observed in Senegal, Mauritania and Mali.

The effect on crops shows up in the Water Requirement Satisfaction Index. For millet at the second dekad of September, FEWS NET reports WRSI values below 90% of average concentrated in the northern Sahelian zone, with the sharpest deficits — under 50%, and in the 51–70% band — appearing in localized areas of central Mauritania, central Mali, western Niger and northern Chad.

FEWS NET notes that near-normal rainfall over the eastern Sahel and above-normal rainfall over the central and western Sahel through early October could bring brief relief, while cautioning that a full recovery is not expected. The agency also forecasts average maximum temperatures exceeding 38°C in the first and second weeks of October across much of the Sahel, which it says may drive high evaporative demand.

El Niño background and the October–November outlook

Citing NOAA's Climate Prediction Center probabilistic forecasts issued in September 2026, FEWS NET reports a greater than 90% probability of a very strong El Niño through February 2027. For the October–December 2026 season, the agency says there is a 75% chance of a historic event exceeding the strength of previous El Niño events back to 1950, and that all 22 models in the ensemble forecast a "very strong" El Niño — Niño 3.4 at or above +2.0 °C — from SON 2026 through DJF 2026–27.

On the regional outlook, FEWS NET reports that WMO and C3S forecasts point to above-normal rainfall across the Sahel in October and November, with below-normal rainfall likely over the bimodal areas. The agency says above-average rainfall could support crop maturation and grain filling where crops remain in the field, potentially limiting further yield losses, but warns that localized dry spells remain possible as the rains subside and could affect crops that have not yet matured. Late-season rainfall, it adds, is unlikely to fully offset the accumulated deficits.

FEWS NET also reports that the NMME, WMO and C3S models confidently forecast above-normal October–December temperatures across the region, which could raise evapotranspiration and crop water demand. The agency says continued monitoring will be essential for crops in reproductive and maturation stages in parts of the Sahel, as well as for upcoming irrigated off-season cropping and second-season crops in the bimodal zones.

On rivers, FEWS NET states that based on the NMME extended streamflow forecast, the likelihood of flooding along West Africa's major rivers is extremely low through the end of the season.