#3: A red sunset guarantees good weather
There is a reason this saying has survived for centuries: under the right conditions, it can actually work. Trouble begins when people treat it like a promise. In places where weather systems normally travel from west to east, a red evening sky can indicate dry, stable air to the west, which may indeed suggest fairer weather is approaching. Shift the local weather pattern, wind direction, geography, dust levels, or position of the system, however, and the old rule becomes much less dependable. Meteorologists therefore tend to describe “red sky at night” as a useful observation with limits, not a forecast carved into stone. It belongs to an era when sailors and farmers had to squeeze every possible clue from the horizon.
