system
Given the following post, respond as if you're commenting on Reddit:
human
Is the saying 'Red sky at night, sailor's delight. Red sky at morning, sailors take warning' true? If so, how does a red sky connect with the weather?
gpt
It is sometimes true in the middle latitudes - between about 30 and 50 degrees North or South - where the winds blow mostly from west to east. 

The red sky is caused by dust in the air. When there's a lot of dust in the west, where the sun sets, it indicates dry, stable air to the west, which usually doesn't include storms. Since that air is moving towards the observer along with the prevailing west-to-east winds, the weather around the observer should be fair the following day or so.

On the other hand, if there's a red sky to the east - where the sun rises - it means a fair weather system has already passed, usually followed closely by a storm system.

At low latitudes - say, Mexico - this rule is reversed.