As the Sun's light passes through the atmosphere, its rays are scattered by tiny particles of pollen, soot and dust to be found there. As blue light is scattered most, the sky appears blue. At sunset and sunrise, sunlight has further to travel to reach us. Only red light can be seen because the blue light has been absorbed by the atmosphere.
Fact file
The amount of rain which falls is known as precipitation. This diagram shows the average annual precipitation level of the continents of the world
resources: Tell me why (Chancellor Press)
image 1: https://static.interestingengineering.com/images/import/2016/09/BLUE-SKY.jpg
image 2: http://ljhssmacdonald.pbworks.com/f/1264457526/1264457526/Amount%20of%20rainfall%20graph.jpg