Arizona

There is an old saying among mariners: “Red Sky in Morning – Sailors take warning; Red Sky at Night – Sailor’s Delight.” I asked Alexa about it – is it accurate and where did it originate?

The accuracy is quite impressive for middle latitudes in the Northern Hemisphere. The reddest of red skies occur when there is high atmospheric pressure, and depending on whether that happens at sunrise or sunset, it could mean a storm is brewing. Here’s how it works:

Red Sky at Night (Sailor’s Delight):

• A reddish sunset means that the air is dusty and dry. Since weather in North American latitudes usually moves from west to east, a red sky at sunset means dry weather—good for sailing—is moving east
• A red sunset often means that there are clouds in the east and clear skies to the west, an indication of approaching high pressure and good weather

Red Sky in Morning (Sailors Take Warning):

• A reddish sunrise means that dry air from the west has already passed over us on their way easy, clearing the way for a storm to move in
• Red skies in the morning can mean clouds invading from the west, often the forerunner of approaching storms

Historical Origins

Variations of this adage can be traced back to biblical times and are based on the experiences of mariners who sailed the Earth’s middle latitudes, where storms generally travel from west to east. The most popular version arises during to 1600 to 1800s during the age of sail.

The saying has evolved across cultures – in England, the saying is slightly different: Red sky at night shepherd’s delight, Red sky in the morning, sailor’s warning/shepherds take warning.

So, given the historical lore and somewhat accurate forecasts, we should expect good weather. However, NOAA is forecasting rain most of the day tomorrow. We shall see.

Image courtesy Verna. Click to view enlarged.