Why sometimes night is longer than day?

Question

I have noticed that there are months in the year that nights are longer than the days. What is the reason behind that phenomenon? 

Answer 1

It is due to the tilting of the Earth's axis in relationship to the elliptical plane as it travels around the sun.

Answer 2

This is referred to as solstice. It is the tilting of the earth's axis towards the northern or southern hemisphere. It occurs twice a year. Winter solstice and summer solstice. The opposite is Equinox_equal day and night.