Peak Sun Hour for Major UK Cities

What is the peak sun hour?

The peak sun hour is 1 hour of sunlight at an intensity of 1,000W/m² (92.9W/ft²).

The power rating of solar panels is also measured at 1,000W/m² (92.9W/ft²).

In other words, solar panels placed perpendicular to the direction of sunlight exposure will only output at their rated power when the sunlight exposure intensity reaches 1,000W/m² (92.9W/ft²).

As you know, the sun’s rays only have a chance to reach their maximum intensity during the midday hours. Maximum irradiance up to 1,360W/m² (127.8W/ft²).

But Peak sun hour is not just about the energy gained during the noon hour. It is the sum of all tPeak sun hour is the equivalent value of all the solar energy received during a day.

What can be done with peak sun hour?

The peak sun hour is especially important for DIY solar power system. After planning the total power, you need to calculate how many panels you need based on the peak sun hour of your location.

For example, you want to design a solar power system that can produce 6kWh per day. You plan to use 200W of solar panels. The peak sun hour in your area is 3 hours. Then you need 6kW/(200W x 3) = 10 panels.

Peak Sun Hour in Major UK Cities

Cities	Peak Sun Hour(PSH)
Aberdeen	2.4
Belfast	2.4
Birmingham	2.6
Bristol	2.8
Cambridge	2.7
Cardiff	2.9
Edinburgh	2.4
Glasgow	2.4
Kingston Upon Hull	2.5
Leicester	2.5
Liverpool	2.6
London	2.8
Manchester	2.5
New Castle Upon Tyne	2.5
Oxford	2.7
Plymouth	3.0
Southampton	2.9