When People Relied on Planets, Frogs and Cows to Predict the Weather

On August 1, 1861, British naval officer Robert FitzRoy published the first publicly available modern weather forecast in The Times. In it, he predicted the temperature in London would be 62 degrees Fahrenheit, the sky would be clear and there would be a southwesterly wind. The forecast included several cities throughout the United Kingdom, France, Denmark and the Netherlands, too.

FitzRoy had been observing weather in his position as head of London’s Meteorological Office since 1854. His forecast seven years later was significant because he used new meteorological methods to make his predictions. But the desire to predict the weather is very old. Throughout history, people have made forecasts about the weather based on the position of the planets, the color of the sky and the behavior of animals like frogs and cows. Here’s a look at what some of these observational methods entailed.

Before the 18th century, European and Arab scientists commonly made weather predictions via astrometeorology. The practice rested on the belief that other planets affect the conditions on Earth; by tracing the planets’ movements, astrometeorologists thought they could predict the weather.

“It starts in about the second century CE with Ptolemy of Alexandria in Egypt, and it runs on until the early 18th century in Western Europe,” says Anne Lawrence-Mathers, a history professor at the University of Reading who has written about astrometeorology including for her 2019 monograph, Medieval Meteorology. “It lasted a very long time… But by late 18th century, really, it’s out of fashion, and rich and powerful people would laugh at it rather than take it seriously.”

Ptolemy developed his ideas about how planets affect the weather using Greek astronomy and astrology. Arab astronomers later built on his ideas, and their writings in turn influenced Western European thinkers. One of the core concepts of astrometeorology was that each planet had a unique effect on the Earth. For example: Slow-moving Saturn signified cold, while the comparatively faster Mercury signified warmth.

Ptolemy’s astrometeorological model placed Earth at the center of the universe, something that Polish astronomer Nicolaus Copernicus challenged in the early 16th century with his theory that the sun was at the center. Yet even after European scientists accepted Copernicus’ heliocentric model, figures like the German astronomer Johannes Kepler continued to endorse astrometeorology.

That’s not to say that everyone believed in its accuracy. Almanacs, which printed weather forecasts based on astrometeorology, were both widely read and widely ridiculed. After astrometeorology lost credibility with scientists in the 18th century, almanacs continued to use it to make forecasts (and some still do today).

However, there is another type of forecasting that is even older than astrometeorology, and which persisted well after the development of modern meteorology: local folklore.

Trying to predict the weather by looking at your surroundings is an old human practice. In the first century A.D., Roman author and military commander Pliny the Elder wrote in his Natural History that humans could predict the weather by observing natural phenomena like the sun, the sea, clouds and animal behavior.

Just as weather and climate differ by geographical region, so too does weather lore. In parts of Germany, Austria and Switzerland, local folklore once held that if you kept a tree frog in a jar filled with some water and a little ladder, you could predict the weather based on the frog’s behavior. If the Wetterfrosch, German for “weather frog,” climbed up the ladder, the weather would be sunny and fair. If it went down into the water, the weather would be rainy and foul.

German-language catalogs from the late 18th and early 19th centuries advertised containers with little ladders meant to house these weather frogs. German speakers still sometimes use Wetterfrosch as a humorous word for a meteorologist.

Karol Mullaney-Dignam, an associate professor of history and geography at the University of Limerick, found many types of weather folklore when combing through Ireland’s National Folklore Collection for her research. Some of this folklore involved animal behavior: Cats turning their backs to a fire meant a storm was coming, and cows lying down in the grass signaled it was going to rain. Lawrence-Mathers remembers her grandmother repeating this adage about cows.

Some of the sayings Mullaney-Dignam found in the collection were things she, too, had heard growing up, like “Red sky at night is a shepherd’s delight; red sky in the morning is a shepherd’s warning.” This adage has different variations—some of which are about a “sailor” instead of a “shepherd”—but one of the oldest sources for it is the Gospel of Matthew.

“When it is evening, ye say, It will be fair weather: for the sky is red,” Jesus says in the King James Bible. “And in the morning, It will be foul weather to day: for the sky is red and lowering.”

Mullaney-Dignam says many of her students have never heard of the weather folklore she grew up with. But of all the adages, “red sky” is the one they’re most likely to recognize.