Folklore or fact? Your weather queries answered


So the question is: folklore or fact? We put a few to weather guru Frank Singleton to separate the supposition and superstition from the firm facts. Having worked as Chief Forecaster in the Met Office for many years, and having always been a keen sailor, Frank is in a privileged position to fill us in.

One thing that is worth stressing is that weather lore is of limited value compared to a modern day forecast and Frank's weather website is a very useful one as it is tailor made for sailors.

A backing wind says storms are nigh, Veering winds will clear the sky. Any truth in this? If so, why?

Ahead of a warm front, as you probably learned in your RYA Yachtmaster course, the wind will back from W or NW to SW, S and even SE. This can be a good predictor although not all backing winds will presage a warm front.

Like much weather lore it can help amplify a forecast rather be a forecasting tool in its own right. There is no indication of how strong winds will become, nor when.

As a cold front passes, winds will veer from a SW’ly point ahead of the front to NW behind. So, in this case, the wind veer will be as or after the front has passed. In other words, the cold front clearance will be happening or will have happened.

Further behind the cold front, showers are likely to develop so that the clearing skies will be interrupted by showers, perhaps with thunder. Not such a reliable indicator.

The higher the clouds the better the weather.

Hmm! It all depends on what type of cloud. If there is cumulus cloud, those nice little woolpacks, and the bases are high – around 4000 feet or more, then rain is unlikely.

Similarly, if the cloud is of a mackerel appearance with no mare’s tails, then again, it looks set fair. Ahead of a warm front, however, you will almost always see high cirrus cloud spreading across the sky. It will be high but be a fore-runner of rain some hours later.

When halo rings the moon or sun, rain's approaching on the run.

As the cirrus ahead of a warm front spreads across the sky it often becomes a high uniform layer of cloud known in the trade as cirro-stratus. Such cloud consists of ice crystals, mostly hexagonal plates.

In a similar way to a rainbow being formed as light passes through water drops, light passing through these ice particles is split into the colours of the spectrum. Because of the different geometry, haloes almost always subtend an angle of 22.5 degrees while rainbows have an angle of 45 degrees, ie they are twice as big.

Cirrostratus can create several varieties of halo and these sometime intersect to create 'mock suns'. These will be either side of the real sun on the 22.5 degree halo.