Highlights

The 2023 rainy season is expected to be generally average to wet in the Sahel, with early to normal start dates, late to normal end dates, average dry sequences in the western part and longer tendencies in the eastern part, and overall surplus to average runoff in the main river basins of the Sahel. In the Gulf of Guinea countries, the 2023 major rainy season is expected to have generally average rainfall amounts, normal start, normal to late finish, average to short dry spells and generally average to surplus flows in the coastal basins.

Between May - July 2023 in the region:

Average to surplus rainfall is expected over southern Chad, northern Cameroon;
Over the eastern coast of Nigeria and the northeastern coast of Cameroon rainfall is expected to be average to deficit;
Elsewhere near normal rainfall is expected

Between June and August 2023 in the region:

Average to surplus rainfall is expected over the central eastern Sahel (Niger, Chad), northern Nigeria and extreme northern Cameroon;
Excessive rainfall is expected over the central Sahel (central and western Mali, almost all of Burkina Faso)

Between July and September 2023 in the region :

Medium to excess rainfall is expected over the central eastern Sahel (Niger, Chad), northern Nigeria and Cameroon;
Excessive rainfall is expected over central Sahel (central and western Mali, almost all of Burkina Faso, extreme western Niger);
Average to deficient rainfall is expected over the northeast coast of Cameroon.

This is associated with early to average start dates of the season over the western and central Sahel. Over the eastern Sahel and Sudanian belt, they are expected to be average to early in places, particularly in the southern parts of Mali, Burkina Faso, Chad, extreme eastern Niger, and the northern parts of Nigeria. Normal to late start dates for the season in the southern and southeastern parts of Nigeria. Southwestern Nigeria will have an average to early start.

During the season, medium to longer dry spells are expected in the early part of the season over the Sahelian and Sudanian belts of West Africa and Chad, with a high probability of observing longer rainfall breaks over the eastern half of these belts covering southern Burkina Faso, almost all of the agricultural and pastoral belt of Niger and Chad, and the northern parts of Nigeria During the second half of the rainy season, the dry sequences would be medium to long in places in West Africa and Chad.

Short to medium duration of dry spells at the beginning of the season over the entire southern band from central Côte d'Ivoire to southwestern Nigeria, except for coastal parts of these countries where dry spells are expected to be medium to long, particularly in the second half of the season.

Late to average end of season dates are expected over the Sahelian and Sudanian bands of West Africa and Chad, except in the extreme northwestern part of Niger, northern Burkina Faso, central Mali, and the extreme southern parts of Burkina Faso, where they would be average overall. Late to average end-of-season dates in the extreme southwestern part of Nigeria. However, in southern Nigeria the end of season dates would be rather normal to early.