The sun is bright, obvious really. However its brightness or luminosity when its light reaches earth is greatly decreased because it weakens due to an inverse-square law. This is a law that means if your distance from the sun doubles, the brightness you see decreases by 2²(4). So therefore Jupiter which is 5 times as far away from the sun as us, only receives a 25th of the light we get. Lucky us, you just try sunbathing on Jupiter!
So this begs the question; What if I was ON the sun? How bright actually is the sun?
The simple answer is that the sun is not especially dim.
A single section of the sun’s surface, with the surface area of a postage stamp, would glow with the brightness of over 1,500,000 candles. Probably enough to light up several Cathedrals!
Remember though, this light is constant, if the sun ‘isn’t strong’ on a particular day please do remember, the sun is being extremely strong at every moment. Any lack of sunshine is the Earth’s fault, or yours for staying inside all day.