In summer, it always “seems” that the intensity of sunlight is brighter. On the Winter Solstice, on the other hand, the Sun's maximum height over the horizon is a full 46.8° lower than it is at Summer Solstice. That's not only a difference you can see, it's a difference you can clearly feel in terms of warmth!

What season is the sun brightest?

It's not your imagination, the sun really is brighter in the fall and winter and it's changing fast.

Why is it brighter in summer?

As the Earth circles the Sun during the year, half of the Earth get more or less sunlight than the other half of the Earth. In the summer months, the northern half of the Earth, where we live, tilts towards the Sun. This means we get more sunlight, making the days longer.