The ancient Chinese, according to one YuinChu-Tsih, who claimed to know, believed that if a dragon's eggs were discovered in a lake or stream, then floods were sure to come. In the western world, however, our signs are less exotic.
The swan, for example, can be watched since it is said to be a skilled hydrologist, building its nest high up the river bank when floods are due, but low down near the water when it assesses that rainfall will be less than normal.
Others, however, swear by wasps.
Wasps build their nests in almost any kind of cavity, in hollow trees, attics or in convenient holes in the ground.
Like the swans, however, when they put their nest high on the bank of a stream, a wet summer is expected, but when the nests are near the level of the water, a drought is on the cards.
And their skill on a seasonal scale is also evident from the saying that when the wasps "go to bed early" - when they disappear earlier than usual at the end of summer - it is certain to be a mild winter.
The wasp is also good at short-range forecasting. According to the old rhyme, when
Gnats wheel round in airy ring
And angry wasps begin to sting, then
These, though cloudless be the sky,
Tokens are that rain is nigh.
Now, it is not surprising, one might argue, that the insects have been endowed with these very useful skills since the weather is very important to them as a community.
Ideally, wasps need a mild winter to survive in large numbers, a warm spring for the queens to awake from their hibernation and establish new nests, and a warm and humid summer to increase and multiply into a good swarm.
Given something approaching these conditions, wasps are as busy as bees for most of the summer, but they change their habits noticeably with the approach of autumn.
Throughout the summer, the workers collect protein for their young in the form of small flies or tiny bits of carrion, and take it back to feed the larvae in the nest. The workers' energy requirements during this period are met by the larvae, who conveniently secrete a carbohydrate on which the workers feed.
In late August, however, the queen stops producing larva and as the colony begins to break up the workers have to find their carbohydrates elsewhere. It is at this time of the year that wasps display one of their less endearing characteristics - an apparently irresistible attraction to any sweet commodities in their vicinity.