Some of you may have heard the old rhyme that goes "Red sky at night, sailors delight. Red sky in the morning, sailors warning". It basically means that if the sky is red when the sun sets, then the next day should be a clear and sunny day. And if the sky is red while the sun rises, then the weather will be miserable.

 

I live in the southern hemisphere where the sunrises in the east and sets in the west, and I have found this saying to be usually correct.

 

Can anyone please explain to me why this is? Has it something to do with air pressure? I don't think its pollution because there is little to none where I live.

The same reason that the sky is blue. The atmosphere scatters light, and blue is scattered more strongly than red. More atmosphere, or more stuff in the atmosphere to scatter the light, means that you have more scattering, and that affects the degree of the coloring. A red sky can indicate a high pressure system, so if your weather moves west-east, the saying gives you the location of that high and can help predict the incoming weather. High to the west means good weather coming. High to the east means low pressure to the west, and usually bad weather coming.

I live in the southern hemisphere where the sunrises in the east and sets in the west, and I have found this saying to be usually correct.

I live in the Northern hemisphere and by a bizarre coincidence the sun does exactly the same thing there.