The Guinean Coast is the wettest area in West Africa, which also experiences a longer rainy season than further north in the Sahel. The time series plots show that during the last decades of the 20th century the area experienced dry summers more frequently. There are indications that this pattern is likely to change in the future climate (21st century), with three out of the selected six models projecting an upward precipitation trend. This GFDL CM2.0 projected upward trend is statistically significant, while that by the MPI ECHAM5 and GFDL CM2.1 models are not significant. The remainder of the models show almost no trend in either direction.
Most of the models pick the correct pattern of the annual cycle along the Guinean coast region, an exception being the MIUB ECHO-G model which displaces the rainfall maxima towards the early summer months. In the future climate, the GFDL CM2.0 and the MPI ECHAM5 models project more intense rainfall during the peak of the summer (July and August) with some little evidence of a slight drying in May. The other models do not project any significant changes in precipitation amounts during the summer months.