Rain is such an undeniable requirement within our climate that any approach to a wide range of subjects will take into consideration rainfall prospects for wetter or drier. The positive elements of our climate start with our basic geography.

The entire sub-continent sustained a geological uplift placing its present day altitudes well above even the highest plateaus of most other continents. This uplift, river valleys excluded, created a tableland contained within very well defined escarpments. The coastal plains are barely 100 km wide.
Off our coastline flows the cold Benguela current which originates in the Antarctic seas. In the north it reaches the warm Angolan current and at the southern tip of Africa it collides with the warm Agulhas current. It is the only cold current found between two warm currents and it contributes in no small measure to the unique Namibian climate, in particular the region's aridity. The interplay between the various weather systems and pattern of formation and development creates a unique climatic zone which, contrary to other similar geographical latitudes, makes provision for rainfall patterns incomparable to other similar regions.
With some 90% of Namibia lying more than 2000 foot above sea level, this elevation cools the air, even on the hottest of days, to temperature ranges within which mankind can live.
The sheer elevation-cum-cooling to which an invading airmass is subjected, helps to increase the humidity content of this air, relative to the air temperature.
At 30oS latitude, Africa is the narrowest of the continental land-masses: the ability for moist maritime air to penetrate deep into the interior is a real prospect and again, the cooling by elevation increases the moist air potential.
Continental-interior tropical moisture sources lie some few hundred kilometres northward: the Congo air mass: this too has its moisture potential increased as it ascends the inland escarpments of the northern side of the sub-continent. Its effect is seen in the relatively high rainfall zones in Angola and Zambia, and when it does reach our generally dry environs, it causes some of the most spectacular rains.
In the southern summer, the southern advance of the ITCZ (Inter-Tropical Convergence Zone) establishes a line along which equatorial low pressure vortices can and do develop. The northern end of the Trade Wind regime (even overland) is capable of nudging an individual vortex westward to a position whence tropical rains are to be experienced across a wide belt of the country: a further impetus to advect Congo air.
The west coast escarpment drops to a very narrow coastal belt, beyond which the north-south lie of the continent provides yet another positive feature. The gently drifting (1 to 3 knots) Benguela current features the upwelling:which brings cold water to the surface. This colder zone contracts the air mass above it, creating a weak trough of lower pressure in the upper air, some 10 000 to 15 000 feet above sea-level. The air circulation created by this weak trough makes another opportunity for moister air to flow on its eastern side, southward. A further fact is that any air, drawn southward, will cool as it leaves tropical latitudes. As it cools, so its moisture content increases to the point where condensation (cloud) and eventually, with further cooling, precipitation occurs. The presence of this upper air trough determines the weather patterns of the sub-continent.
The escarpment slows down the eastward movement of a cold front. This creates a zone of weather activity, slowing down the cold front to develop vortices, particularly in the upper air, cut off from the parent vortex and the remainder of the cold front. This new and increasingly active vortex draws in Congo air, in appropriate circumstances. When the edge of the Congo air boundary is already further south than normal, considerable falls across a wide area of Namibia are likely. The presence of the weak upper-air trough is also useful in this regard.
he north-south coastal configuration assists the occasional, roughly every 10 years and mid-decade, intrusion of the Benguela El Nino.
The escarpment has a positive role in this likely development. For reasons not yet fully explained or understood, a southward drift of both surface and depth waters occurs along the coast, penetrating even beyond the Walvis Bay latitudes. As with the Pacific El Nino, there is a remarkable change of marine environment accompanied by a rise in Sea Surface Temperatures. This belt of warm water, barely 100km wide, created by the Benguela El Nino, has proved to be a very attractive resting place for a low-pressure area. When (and this occurs some 80% of the time) this event occurs in tandem with a Pacific La Nina, the records show excessively wet years with both Productive and Substantial falls in abundance. The coupled events 1934, 1974 and 1976 are classic examples.
A similar result occurs when, without warm water depth, only the Sea Surface Temperature becomes anomalously warm due to insolation and limited wind-flow cooling. This event, again coupled with La Nina, also provides a generally wetter than normal season: 1950 and 2000 provide good examples. The occasions when either of these warm water events occurs, but without a defined La Nina coupling (1963 for example) good falls occur sporadically.