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Peak sun hours are a vital measurement to understand when considering the installation of solar panels. Peak sun hours are not the same as total sunlight hours because not every hour of sunlight during the day has enough strength and solar insolation to qualify as a peak sun hour. The rule of thumb is that a peak sun hour is when the intensity of the sun that is hitting your solar panel is providing at least 1,000 watts per square meter. This is an arbitrary number, but it is a number where most solar panels will be producing an efficient output and not underperforming due to sunshine that is not strong enough or direct enough.

Sunlight hits the earth directly at the equator. This is why the equator has a latitude of zero degrees. The latitude of Douglas is 47.6. Knowing the latitude of Douglas can help you plan for your solar panel setup, as the larger the latitude the more variance you will see throughout the year for total daily sunlight hours.

A tracking mount will increase the average peak sun hours for a solar power system. Think about a panel that is tracking the sun in the sky vs a panel that is fixed and not moving: you will see a higher efficiency ratio of productions. A 1-axis mount will track the sun from East to West from sunrise to sunset and move on a single axis of rotation. A 2-axis mount will track the Sun from East to West the same as a 1-axis mount would, but it will also track the angle of the sun in the sky as it slowly varies season to season. A 2-axis mount is more necessary in high latitude regions where the angle of the sun in the sky changes dramatically between each equinox.

Although weather predicting technology has greatly evolved over time, it is still a rather unpredictable factor that will affect the amount of peak sun hours your solar power system will receive. Cloudy days for example will usually have lower peak sun hours that a clear sunny day. And areas that usually have more average sunny days per year will probably have higher peak sun hours that areas that are often overcast or stormy.

By taking the latitude of Douglas one can get a close estimate of the amount of average peak sun hours per day for the geographical area. It varies with technology and the type of solar panel mount you use, but for a fixed mount solar panel in Douglas one can expect close to 4.5 average peak sun hours per day. With a 1-axis tracking mount you would get 6 hours per day, and 6.2 hours per day with a 2-axis tracking mount that tracks the sun everywhere in the sky.