… sailors take warning. Red sky at night, sailors’ delight.
Dating back to biblical times, this ancient rhyme was upheld both by mariners and shepherds as sound Jewish wisdom.
Although not entirely accurate, for the most part, mariners could and can broadly forecast using this rhyme.
If the morning skies are of an orange-red glow, it signifies a high-pressure air mass with stable air-trapping particles, like dust, which scatters the sun’s blue light. This high pressure is moving towards the east, and a low-pressure system moves in from the west. Conversely, in order to see “red sky” in the evening, high-pressure air mass from the west scatters the blue light in the atmospheric particles, leaving the orange-red glow.
High-pressure air mass signifies stable weather, while low pressure signifies unstable weather.