How the weather influences the nation’s use of electricity

Municipal purchases and sales of electricity followed a usual, but very interesting, seasonal pattern in the last three months of 2015, according to Stats SA’s latest Quarterly financial statistics of municipalities report.


Published every quarter, the report provides an indication of the financial status of South Africa’s 278 municipalities, including data on where municipalities source their income from, and what they spend money on. Trading in electricity is an important source of income. Acting as intermediaries, municipalities buy electricity from Eskom in bulk and then re-sell it to various customers, including homes, businesses and government.


In the chart below, do you notice how both sales and purchases of electricity tend to peak in the September quarter (covering the months of July, August and September) and slump in the March quarter (covering the months of January, February and March)?



This is because of the weather in the southern hemisphere. Customers use less electricity during the hottest months of the year, resulting in a fall in demand. Municipal electricity sales and purchases reach their lowest levels in the March quarter. The opposite is true in winter. As customers use more electricity to keep themselves warm, municipalities buy and sell more to meet the rising demand, peaking in the September quarter.


As the weather heats up during the months of October, November and December (i.e. the December quarter), demand starts to fall again.


Electricity demand also differs depending on population and economic size. Gauteng was the largest contributor to sales of electricity in the December 2015 quarter, followed by KwaZulu-Natal and Western Cape. The smallest contributing province was Northern Cape.



Download the complete publication here.

For provincial level data, contact Malibongwe Mhemhe at

Photograph: Chris Kirchhoff,