What happened?
It might appear that, with the time change, there was a season change too. The leap from winter to summer appears to have been made.
While cooler weather can still occur, but the likelihood of late frost appears to have receded, though.
The feature is the very high temperatures recorded across the far north and the generally warmer ranges recorded, by day and night, for the rest of Namibia.

 Temperatures fringing on blood temperatures are to be expected from mid-September, rather than late August. This might seem like just a few days difference, but it represents an advance of days of abnormal heat, thus desiccation, across a range of land which already moisture-short. The effects go far beyond the range of temperature extremes.
Across a broader spectrum, the world's weather has shown similar results to warmer conditions. Two hurricanes of maximum intensity definition have formed in the Caribbean: these demand sea surface temperatures above 28oC for several days, these temperatures have been in the 30 range. The ITCZ, currently across the Sahel, has shown a range of daily variation beyond the normal stability of position.  Closer to home though, the sea temperatures off the Cape have subsided somewhat, but are still above normal. This last fact can explain the decrease in stormy activity occurring during the past few days. Abnormal conditions need explanation: does Global Warming fit this bill?
With the increased heat, the dangers of such warmth cannot be ignored. Veld fires are probably a daily event across the country, apart from human error, spontaneous combustion is also a likely response to excessive heat on a dry environment. The growing likelihood of increased daytime winds and wind-gusts is the response to heat, local atmospheric overheating, and a local drop in air pressure leading to the movement of air: wind. Local overheating also develops dust-devils: more wind gusts. But wind spreads fire quickly, the speed of the spread exceeds the speeds at which animal life, let alone humans, can get out of the way.
Summertime temperatures also induce the return of the more unwanted insects and their wares.