The relative humidity fluctuates seasonally between a mean minimum of 60% during the dry season (January) to a mean maximum of 80% during the rainy season (July) near the coast, declining steadily from the coast towards the north of the countries. The SS, NGS, SGS, FSM zone and RF were designated as 1–5 in the correlation analysis, following the order of increasing precipitation. Three sites in the coastal savanna of Ghana were analyzed as part of the SS because of their similar climate.