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It goes without saying that throughout the year the amount of sunlight in any given day is going to vary. The time of year and weather will have a strong influence on daily sunshine. Looking at the average amount of peak sunshine hours in a day during an entire year stretch is a valuable exercise when trying to determine the amount and type of solar panels you need to install to power your business or your home. 4.9 peak sun hours means that in Bureau on average there are 4.9 hours a day where the sun is strong enough for solar panels to harness its energy. This number is less than the amount of total sunlight hours in a day because there are times during the day (ex. sunrise and sunset) where the sun is not strong enough to benefit solar panels.

The latitude of the location is important for measuring peak sun hours. The latitude determines how much overall sunlight there will be in a day. With a given latitude, time and date, one can accurately determine when sunrise and sunset will occur. Areas with latitudes closer to the equator will have a more consistent range of solar insolation throughout the year. Whereas areas closer to the poles will have a greater variance during the summer and winter months due to their higher latitudes.

The sun moves through the sky during the day, and changes positions in the sky throughout the year as the seasons change. A fixed solar panel remains fixed in position during this movement. So, although it is effective in capturing sunlight, a 1-axis or 2-axis panel can be more efficient. A 1-axis panel tracks the sun's movement throughout the day from sunrise to sunset. In addition to that, the 2-axis panel also accounts for the movement throughout the year.

Weather is a big determinate of average peak sun hours each day. There are many aspects of weather that can increase or lessen the peak sun hours in a day in a particular location. For example cloud coverage is a crucial variable. And more importantly, what type of cloud coverage; thin scattered clouds will have less diminishing power on the solar insolation than thick rainy storm clouds. Sometimes long periods of sunny days are rare in certain locations, this would increase average peak sun hours for that time-frame

In Bureau the average yearly peak sun hours for a fixed tilt non-tracking solar panel mount is 4.9. 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 hours if you upgrade to a 2-axis solar panel.