MOO Reports:
DIY Weather Forecasting

Can cloud formations, animal behaviour and legend really tell us what the weather will be like? MOO investigates

For thousands of years, man has desired to be able to forecast the weather. Some of the earliest forecasting took place back in Egyptian times, when farmers examined the weather in order to know when the River Nile would flood. Since then, our ancestors have sought to find clues to what weather may come in the future. These clues have become myths and legends over the years, and whilst some are scientifically accurate, others should be just left as myth. The are several forms that these predictions may take. One kind is long term weather forecasting. Examples of these are common and include:

"When oak is out before the ash, for sure man can expect a splash"

Additionally, some people claimed that they could forecast the weather at Christmas depending on what the weather was like at Easter, and vice versa. Other cases relate the summer conditions to animal behaviour in the winter. There is no statistical evidence for any of these predictions being true regularly.

Another popular way of forecasting weather is linking certain weather to certain days of the year. Weather is most commonly linked to saint's days, for instance the days devoted to St. Bartholomew, St. Vitus and St. Andrew all have weather types linked to them. In the United States, St. Luke's Day in October is traditionally warm and sunny. In England, it is St. Swithun's Day in July which is most famous for its link to weather. The traditional rhyme says:

"Oh if St. Swithun's Day is fair, for forty days it shall rain nay mair,
But if St. Swithun's Day be wet, for forty days it raineth yet."

Again, this particular myth and others of its type have been proved to be statistically inaccurate. This legend may have originated as pressure, both high or low, can become lodged over the British Isles in July, causing long periods of similar weather.

More accurate are rhymes and traditions concerning the clouds. Probably the most famous is:

"Red sky at night, shepherds' delight,
Red sky at morning, shepherds' warning."

The saying is based on a common cloud pattern; firstly cirrus, followed by cirrostratus, then altostratus and finally nimbostratus. Morning red sky indicates that the rising sun is shining on the cirrus or cirrostratus, which means that the stormy nimbostratus is likely to follow from the west. Evening red sky means that bad weather clouds are likely to move away in an easterly direction.

Overall, the most useful observations are those which point towards another weather condition in the near future. However, none of these is foolproof, and of course weather broadcasts are far more accurate!



. 1999-2003 Justin Taylor / John Dray

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