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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 Vergennes throughout the year can help you better estimate the amount of solar panels you will need to power your business or home.

Sunlight hits the earth directly at the equator. This is why the equator has a latitude of zero degrees. The latitude of Vergennes is 37.9. Knowing the latitude of Vergennes 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.

Weather is one of the major culprits that will cause inconsistent total peak sun hours for any given day. The sunrise and sunset will always be predictable every day, but the weather is hard to predict and cloud coverage can greatly diminish the efficiency of a solar power system on any given day. On the bright side, a location that is known to have cloudy weather a majority of the year could have unexpectedly more sunny days, so it can go both ways.

Since we know the latitude of Vergennes we can take the average amount of total sunlight hours and estimate that with a fixed solar panel there would be an average of 4.7 peak sun hours per day. 5.6 hours per day with a 1-axis tracking mount that tracks the sun from sunrise to sunset, and 6.3 hours with a 2-axis tracking mount that tracks the sun everywhere in the sky.