Peak Sun Hours South Africa: Numbers, And How To Calculate?

Here's a table about the daily average peak sun hours in South Africa.

Peak sun hours (South Africa)

RankProvinceDaily Average Peak Sun Hours
(Solar irradiance kWh/m2)
1Northern Cape6.2 hours
2North West5.9 hours
3Free State5.8 hours
4Gauteng5.5 hours
5Limpopo5.4 hours
6Mpumalanga5.4 hours
7Western Cape5.4 hours
8Eastern Cape5.2 hours
10KwaZulu-Natal4.9 hours


  • On average South Africa receives between 4.9 - 6.2 peak sun hours daily.

importance of peak sun hours

Solar panels are designed to produce their rated power rating under STC (standard test conditions), which are: 1 kWh of solar irradiance, 25°C (77°F) temperature, and 1.5 air mass.

1 Peak sun hour = 1 kWh/meter2 of sunlight intensity (solar irradiance).

Why consider peak sun hours?

  1. It helps to select the ideal size solar system for your house/RV rooftop to fulfill your electricity need.
  2. It helps to give an estimated output from solar panels.

how to use peak sun hours?

For example:

  • Daily electricity need = 10kWh
  • Daily average peak sun hours = 5
(10 kWh ÷ 5) x 1.3 = 2.6 kWh or 2600 watts
2600 / 300 watt solar panel = 8.6 (300 watt) solar plates required

Related Post: Solar Panel Output Calculator

peak sun hours map south Africa

Peak Sun Hours Map South Africa

Peak sun hours (south Africa): FAQs

Average peak sun hours in Pretoria

On average, Pretoria receives about 5.3 peak sun hours daily.

Average peak sun hours in Johannesburg

On average, Johannesburg receives about 5.4 peak sun hours daily.

Average peak sun hours in cape town

On average, cape town receives about 5.2 peak sun hours daily.

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Chris Tsitouris is a renewable energy professional with 10+ years of experience as Director of Engineering at Solar Spectrum, previously working as Project Manager at SunPower and Energy Analyst at the National Renewable Energy Laboratory. As a thought leader, Chris has authored numerous articles and research papers.

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