How much should my solar panels produce in winter in South Africa?
Winter output in South Africa is lower than summer, but less than many people expect – especially in the sunny north and Karoo.
Typical winter and summer numbers
The table below shows how much a well-placed 1 kWp system (north-facing, 25° tilt) is expected to produce per day in each town in June and December. Multiply by your system size – for example, a 5 kWp system produces about five times the figure shown.
| Town | June (winter) | December (summer) |
|---|---|---|
| Johannesburg | 4.6 | 4.5 |
| Pretoria | 4.7 | 4.5 |
| Cape Town | 2.9 | 6.0 |
| Durban | 3.7 | 4.0 |
| Gqeberha | 3.4 | 5.3 |
| Bloemfontein | 4.5 | 5.1 |
| Polokwane | 4.8 | 4.3 |
Source: PVGIS (European Commission JRC), typical year. 1 kWp, north-facing, 25° tilt, 14% system losses.
Why output drops in winter
- Shorter days and a lower sun angle.
- Long shadows from trees, walls and neighbouring buildings.
- Cloud and rain, especially in the Western Cape.
- Dust that isn't washed off by summer rain in the interior.
Check your own system
Use our free health check: pick your nearest town, enter your system size and a recent day's output, and we'll compare it to expected values from European Commission PVGIS data.
Solar systems carry dangerous voltages. Only do the safe checks listed. If unsure, call a pro.
Common questions
- Is lower output in winter a fault?
- Usually not. Inland areas (Gauteng, Limpopo, Free State) produce about as much per kWp in winter as in summer, while coastal winter-rainfall areas like Cape Town and Gqeberha drop noticeably – Cape Town's June output is roughly half of its December output. A much bigger drop, or a drop on clear days, can mean shading, dirty panels or a faulty string.
- Should I clean my panels in winter?
- If they're dusty, rinse them with a garden hose from the ground. Never climb onto the roof yourself.