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The average amount of peak sun hours in a day is a different and more useful number as it relates to solar panels than total sun hours. Total sun hours are exactly what you would expect; the total amount of hours that the sun is out during a 24 hour period. Peak sun hours, on the other hand, are the total number of hours in a day where the sunshine is strong enough to to be absorbed and used by solar panels. Sunlight early in the morning or late at night is often not strong enough to count toward peak sun hours. Because of this, total sun hours will always be more than peak sun hours. Looking at the average peak sun hours in Du Quoin throughout the year can help you better estimate the amount of solar panels you will need to power your business or home.

Your latitude is an indicator of when the sunrises and sunsets and certain times of the year. If you live near the equator with a latitude of near zero, the sun will rise and set close to the same time all year resulting in consistent total sunlight hours per day. If you live near the poles, the time of sunrise and sunset will vary dramatically with each season, resulting in long days for part of the year and very short days at other times. So, locations closer to the equator will have more consistent amounts of peak sun hours throughout the year than locations closer to the poles.

There are a few ways to increase average peak sun hours per year for your solar power system. One way is to use a tracking mount solar panel instead of a fixed tilt solar panel. A 1-axis mount will track the sun throughout the sky from sunrise to sunset, giving your panel a more efficient facing direction towards the sun throughout the day. A 2-axis solar panel will track the sun in the sky throughout the day, but also change and follow the angle of the sun in the sky throughout the year. Both of these axis system solar panels will produce higher average peak sun hours than a fixed solar panel.

Peak sun hours are greatly affected by weather patterns. Cloud coverage is a huge factor in peak sun hours per day because heavy cloud coverage will diminish the power of the solar insolation. You can use historical climate data to estimate average cloud and weather coverage, but it will obviously vary slightly from year to year.

In Du Quoin the average yearly peak sun hours for a fixed tilt non-tracking solar panel mount is 4.7. This is for a fixed panel mounted at an angle that is equal to the latitude of the location for the entire year. The amount of peak sun hours increases to 5.6 hours if you are using a 1-axis panel, and to 6.4 hours if you upgrade to a 2-axis solar panel.