Season of mists and mellow fruitfulness - riding in fog

I'm pretty sure Keats didn't ride a motorcycle, but it's not unusual for spells of settled weather to develop during November and fog can be a major problem. Warm air can still make its way up from the continent and it holds more moisture than during the winter months but nights are long, hence fog may form quite readily and be slow to clear.

Riding in fog, particularly at night, is probably my least favourite part of biking, and if I can I'll stay put. I still remember two trips vividly. The first was a ride to my girlfriend's near West Drayton from Maidstone on the old 125 very early in my riding career that took me twice as long as expected because the fog came down. I very nearly didn't make it because at one point following the kerb I didn't notice I had drifted off the main carriageway of the A40 into a slip road and nearly into the armco of the bend itself. All that saved me was that the fog was so thick I was only doing about 25mph. The second one that sticks out was a beautiful afternoon run from London to GCHQ at Cheltenham that turned into a nightmare of freezing fog, traffic jams and accidents on the way back.

But sometimes it has to be done. So what are the problems and how best to deal with them? Like all other weather-driven hazards, first stop is the weather forecast. Forewarned is forearmed. Find out what the day-long forecast is. Whilst fog may be slow to clear in the morning, it's pretty obvious when you wake up in it. But if the weather changes and become clear and still during the day, fog can easily be a problem on the dark ride home.

On the bike, the first problem is simply seeing out the helmet. The visor gets covered with water droplets on the outside and mists up on the inside from your breath.

Wax polish like Mr Sheen on the outside helps the water bead up and run off. Often you can just turn your head to clear your view - wiping with a glove just smears the oily crud on your glove across the visor and makes it even more difficult to see as well as scratching it. If the visor gets covered in salt spray or road film, a damp cloth kept in a ziplock bag (I spray that with Mr Sheen too) can clean and re-wax the visor.

Seeing as holding your breath all the way home is impractical, on the inside and on glasses an anti-mist treatment will help. You can get various spray cans and other treatments and they mostly seem to help a bit, although quite honestly the best results I obtained when despatching were using Fairy Liquid - a dab of the neat stuff, polished on till dry with a clean cloth. Breath deflectors can also help, but I've never yet found a helmet that demisted itself from the vents that were supposed to perform that trick. Keep some polish and antimist at work, and you can re-treat before you ride home in the dark! So a bit of prep can save lots of hassle later.

Fog also makes you cold. Not only is the temperature in fog lower, but fog is water droplets and just like rain that chills you too. So not a bad idea to put waterproofs on, as well as something to keep you warm!

Having sorted yourself out, make sure the bike is in good shape too, with properly inflated tyres and smoothly operating controls. People buy rat bikes for this kind of weather, which is fine so long as everything works without thought - you need every ounce of attention for riding, not to deal with sticky throttle cables, slipping clutches, dodgy brakes or cheap n nasty tyres.

It's pretty obvious that lights should be clean and working, but it's also important you have dipped beam adjusted properly. Too low and you won't get any forward vision, too high and it'll just light the fog up and bounce back at you - higher output bulbs can actually be a disadvantage when this happens.

You still need to look for clues to where the road goes. Your normal clues will be invisible and one of the effects that can have is a feeling of 'dislocation'. Even on a road you thought you knew well, hazards you've seen dozens of times and dealt with without thinking will leap out and surprise you. So use what you can see.

Reflective posts give useful advice. As you find red to the left and white to the right, if you can only see red markers ahead, you must be looking at a right and bend and vice versa. Cateyes will warn you of hazards (they'll get closer) and solid lines (closer still), which are usually found on bends or crests. Coloured cat-eyes (red to the left, amber to the right, white between lanes, green where vehicles leave or join a carriageway) are very useful to keep you on track, as are the white lines themselves.

If you can't see the catseyes, the hazard line will still give early warning of a problem ahead - a triangular sign may reveal exactly what it is. Other white paint at the side and cross hatchings at the centre of the road will warn you of side-turnings and laybys (see my story about running off the A40 above) as well as central refuges that may have unlit bollards in them!

In general I try to follow the centre line rather than the left hand edge of the road - it keeps you further from dangers to the left which will be harder to see. Oncoming cars will normally have their lights lit but spotting the side of a car isn't easy.

Most of the danger in fog comes from behind. Think about it - YOU control your following distance and speed but you can't control the guy behind!. As you're unlikely to have a fog light (unless you are very lucky), if you do a lot of foggy miles it might be worth fitting one. I've seen riders using bicycle LEDs and was surprised how effective they were. Reflective stuff can help you be seen from behind too but it generally needs to be low down because everyone is driving on dip beam and flat beam front fog lights. A Sam Browne or vest is too high to be much use - Aerostich Roadcrafters have huge Scotchlite panels at the ankles and are highly visible.

The other thing that cold and moisture affects is grip. Where the car tyres run will often be dry, but to either side of the tracks it's quite likely to be damp, as will painted markings and metal surfaces like manhole covers, so you need to plan lines and where you're braking more carefully. Particularly if you have soft compound tyres, they don't usually warm up properly and may be reluctant to stick to cold, damp surfaces.

Most people follow far too close in fog. Two errors. The first error is 'following'. As a kid I remember driving through the Swiss Alps and my father turned into a garage to fill up... half a dozen cars all followed us into the forecourt, looked a bit confused then back out onto the road. Ride your own ride, not the guy in front's. The second is being too close. That wet surface requires decent stopping distances, not least because the bloke behind YOU will be too close so you have to leave room for him to stop too. On a bike the two problems compound themselves. The bloke behind WILL follow you - and you haven't got a fog light for him to see from further back, remember? So he'll be right on your tail. It's doubly important that you keep a safe distance and to keep a dominant position. Start messing with extended positioning in fog and the bloke behind will start doing stupid things.

They also drive too fast. Drop your speed and remember the "stop in the distance you can see is clear" rule. If you can't, you really are in big trouble.

Work out where the fog will be a problem. It's usually one of two types. Low cloud, so likely to be worse on tops of hills, or caused by cold air at ground level after a still, clear day, where the fog generally pools in low-lying areas.

I get both types at home, living on what passes for a high hill in Kent. Some mornings I'll wake up in thick fog, yet two miles down the road and 100m lower, it's grey but clear. I know in this case that the fog is likely to be a problem on other hills, including where the M20 crosses the North Downs on the way to London, but elsewhere it'll be mostly clear. Other days, we're in cloudless blue sky. Now if there is fog forecast, it will be two miles down the road in the river valley, and most of the M20 will be foggy. A third form of fog is the sea-fret. This is typically a phenomenon of the North Sea coast when the wind blowing on shore crosses a band of very cold water running down the coast. This causes fog which gives the coast a cold, damp day when just a couple of miles inland there may be warm, bright sunshine. The north Kent coast is particularly prone to this in spring.

In some ways patchy fog is more difficult to deal with than the real clag, because you never quite know where you might come across it, how thick it is or how long it'll last, though you can make some educated guesses. Even small towns are generally a bit warmer than the surrounding countryside so can be clear but fog can form in the country. Meadows and river valleys are classic places for fog to form when it's still, so even on a clear night, don't be surprised to turn a corner and run into fog. Don't be tempted to blast into a wispy looking bit of mist drifting across the road. It could be a lot thicker than you think.

Like most bits of riding, whilst fog may seem a big problem, there's actually a lot of things you can do to make it safer, if not enjoyable.