West Africa's 2026 rainy season begins normally but El Nino strengthening raises autumn flood and drought risk

Summary

West Africa's 2026 rainy season opened with broadly normal to above-average rainfall in the coastal bimodal zones, including southern Nigeria, Ghana, Côte d'Ivoire, Cameroon and the Congo Basin, according to FEWS NET's June 2026 seasonal monitor. The monsoon trough is advancing northward toward the Sahel on a roughly average schedule. However, the rapid intensification of El Nino in the tropical Pacific, which carries an 84% probability of reaching strong or very strong status by September-November 2026, introduces a significant unknown for the second half of the West Africa Monsoon season. Regional outlooks from CILSS (the inter-governmental authority on drought and food security in the Sahel) warn of divergent conditions: potential flooding in western coastal countries, central Mali and northern Nigeria in September-October, contrasted with potential below-normal rainfall in other Sahelian sub-regions. The pattern is a risk multiplier for the 2026 cereal harvests that Sahelian smallholder farmers depend on.

The split

West African agricultural and food security organisations, including FEWS NET, the WFP and CILSS, covered the onset positively but flagged the El Nino risk for the Sahelian phase. National meteorological agencies in Nigeria, Senegal, Mali and Niger communicated the dual-risk outlook to farmers through agricultural advisory services. International climate press focused on the El Nino connection, noting that the 2023-24 El Nino had contributed to below-normal Sahel rainfall and harvest shortfalls. Humanitarian organisations tracked the early-season food security situation in the three-country Sahel region, where existing food insecurity from conflict and prior weather disruptions means any additional shock from late-season drought would require emergency response.

By the numbers

• Normal to above-average, early rainfall classification for bimodal West Africa (March-June 2026)
• 84%, probability that the Pacific El Nino reaches strong or very strong status by September-November 2026
• September-October, the period of highest projected flood risk in western coastal countries, central Mali and northern Nigeria
• Sahelian rains typically peak July-August; El Nino effects on the Sahel typically appear from September

Why it matters

The West Africa Monsoon is the primary driver of agricultural production for approximately 200 million people in the Sahel and Sub-Saharan West Africa. A season that begins normally but is disrupted by El Nino in September-October can still cause significant harvest shortfalls, particularly in millet, sorghum and cowpea. The 2026 risk profile is elevated because it coincides with already-high food insecurity in Mali, Niger, Burkina Faso and Chad, ongoing armed conflict in the Sahel that limits government response capacity, and a global corn stocks environment that leaves less cushion for emergency food imports.

What to watch

• FEWS NET monthly seasonal monitors through September and October 2026
• Whether El Nino's intensification shifts the monsoon trough southward earlier than normal in August
• WFP and OCHA emergency food needs assessments for the Sahel in October and November 2026
• Whether flooding in coastal countries and drought in inland areas materialise simultaneously, stretching regional response capacity