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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.

If you open the newspaper in the morning or watch the weather channel on the news you can get an accurate prediction of sunrise and sunset each day for Duncan. However, still knowing that the latitude of Duncan is 43.1 can be a helpful number for your solar panel setup and planning. The closer your latitude is to zero the closer you are to the equator. At the equator you find the most consistent total sunlight hours throughout any given day of the year. As your latitude increases you can see larger discrepancies of daily sunlight hours during the year. For example, having very long summer days and very short and dark winter days

Throughout the day the sun obviously moves throughout the Duncan sky. The suns position in the sky also changes throughout the year with the seasons. A fixed solar panel does not accommodate for these changes. However, a 1-axis panel rotates and follows the sun’s path during the day. A 2-axis panel both follows the sun’s daily path as well as the seasonal differences

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.

We can take the latitude of Duncan and use that number to know the amount of total sunlight hours in the region from sunlight to sunset and estimate that with a fixed solar panel, Duncan will receive 4.6 average peak sun hours per day. This number can be increased to 6 hours by using a 1-axis tracking mount, or 6.2 hours from a 2-axis tracking mount.