Sunshine duration is the amount of time that the sun shines in a day!
Sometimes the sky is cloudy, and we don't see the sun all day. Other times, the sun is out and shining bright!
Scientists measure sunshine duration using a device called a sunshine recorder. It's like a little weather station that sits outside and has a special glass ball on it.
When the sun shines on the glass ball, it makes a little mark on a piece of paper underneath. The length of the mark tells us how long the sun was shining for during that time period.
So, when we say that the sunshine duration was four hours, that means the sun was shining for four hours straight!
Knowing how long the sun shines for is important for lots of things, like helping farmers know when to plant their crops or helping us understand how much energy we can get from the sun to power our homes.