For centuries our ancestors have predicted the weather by looking at the sky, or by watching the behaviour of animals or plants. Weather lore, indeed, in the form of popular sayings which have been handed down through generations, is to be found in almost every culture in the world.
In general, any saying which purports to give a long-range forecast of the weather may be discarded as nonsense. The popular belief about St Swithin's Day, for instance, should not be taken seriously. Neither should the assertion that abundant berries on the holly bush are an indication of a hard winter to come, allegedly because the berries will sustain the birds in the expected harsh conditions. A moment's thought might suggest that the holly bush is more likely to be reacting to the weather of the previous summer.
It may be, however, that sayings which predict the short-term prospects, particularly when based on the behaviour of animals, should not be discarded quite so lightly. It is sometimes suggested that birds and animals may be more sensitive to changes in atmospheric pressure or humidity than humans, and that this may help them to anticipate the weather. This, perhaps, may explain the enviable reputation of the sheep in this regard.
According to our ancestors, any odd behaviour on the part of our woolly friends should not be dismissed as mere eccentricity, but should be seen as a clear signal as to future weather. All that is necessary to glean an accurate forecast, apparently, is to be able to interpret these signs correctly.
If, for example, sheep feed uphill and scatter themselves over a wide area, it is a sure sign of fine weather to come. If, on the other hand, they stay on low ground, then rain is near. With an approaching storm, the animals first become frisky, leap about and butt each other, but as bad weather becomes imminent they huddle together under trees or close to bushes - no doubt for the most sensible of reasons.
Sheep are also said to eat greedily before a storm, but sparingly in wintertime before a thaw.
The Greek poet Aratus, who was an acknowledged expert on weather lore in the 2nd century BC, encapsulated much of this valuable advice in a rhyme:
The shepherd, as afield
his charge he drives,
From his own flock
prognostics oft derives;
When homeward, as the
shades of night descend,
Reluctantly and slow
their way they wend,
Stray from the flock,
and linger one by one,
Heedless of shepherd's
voice and missive stone,
When they impetuous
seek the grassy plain,
He marks the advent of
some storm or rain.