Many experienced sailors seem to have an uncanny knack of foretelling the weather just by looking at the sky.
Of course they may be interpreting the sky in the light of the latest Shipping Forecast - but quite often a glance at the sky can tell you as much as a synoptic chart or a strong wind warning. Indeed the sky can provide its own strong wind warning - or the reassurance that there is nothing to worry about.
Being able to read the weather from the sky is an essential skill, especially for sailors venturing far offshore who may find themselves without access to other sources of weather information. (Think Robin Knox Johnston in the recent Velux 5 Oceans race, when his computers and communications equipment failed, and his only other source of weather info, apart from his trusty barometer, was direct observation).
And if you want to develop this skill, there's no better place to start than a book called Instant Weather Forecasting by Alan Watts, just published in its third edition by Adlard Coles Nautical at £7.99.
First published in 1968, it's never been out of print for nearly 40 years, selling well to walkers, farmers, fishermen, golfers - in fact anyone who wants to enjoy the great outdoors - as well as providing an essential guide for yachtsmen. It is a genuine bestseller, with some 750,000 copies sold, in a dozen languages.
The beauty of the book is its simplicity. There are lots of serious and detailed textbooks about the weather which can be very difficult to digest. This little book sets out to make it all as simple and accessible as possible.
It does this through the medium of full-page colour pictures - 24 of them - each showing different moods of the sky, and each accompanied by an opposite page of clearly set out information about what that type of sky is likely to mean, in terms of approaching weather.
Likely changes in wind, visibility, precipitation, cloud, temperature and pressure are explained, along with the all important timescale during which those changes are likely to occur.
The book is only intended for use in “temperate latitudes where depressions and anticyclones chase one another around the hemisphere,” says the author. But then, that's where most of us do our sailing.
And this useful guide starts with a really good general introduction to the nature of those depressions and anticyclones, and how and why they govern our weather.
This attractive and reasonably priced book deserves a place on board every cruising yacht. Compare the sky around you with the pictures, absorb the author's predictions, and you'll soon share the old salts' uncanny knack of knowing when and why the wind and rain can be expected.
