“Red sky in morning, sailor take warning. Red sky at night, a sailor’s delight” So goes the adage. The saying is most reliable when weather systems predominantly come from the west as they do in the United States. A red sky appears when dust and small particles are trapped in the atmosphere by high pressure. This scatters blue light leaving only red light to give the sky its notable appearance. A red sky at sunset means high pressure is moving in from the west, so therefore the next day will usually be dry and pleasant. Red sky in the morning appears due to the high-pressure weather system having already moved east meaning the good weather has passed, most likely making way for a wet and windy low-pressure system. Hence “sailor take warning.” Continue reading →