September 14 - Day 127 - 'Enveloped in a common mist, we seem to walk in clearness ourselves, and behold only the mist that enshrouds others.' George Eliot

It was certainly autumnal this morning but having seen the weather forecast, I set off particularly early to avoid the worse of the rain - and managed it. Earlier in the year, I gave you the Met Office definitions of light and heavy rain. On the way to work and seeing the mist surrounding me, I thought I’d remind myself about the difference between mist and fog.

Interestingly, there is international agreement on this one. Both are created by tiny droplets falling in the air and the difference between them is purely down to how far you can see through them. When you can see less than 1km (or 0.6 miles if you think like I do) then it is fog, when you can see further than this, it is called mist.

What is interesting, or at least it is to me when I get frustrated about cars without lights in this sort of weather, is the Highway Code says,

‘You MUST use headlights when visibility is seriously reduced, generally when you cannot see for more than 100 metres (328 feet). You may also use front or rear fog lights but you MUST switch them off when visibility improves.’

So, that suggests that even though between 101 metres and 1km the weather is defined as fog and not mist, there is no requirement to use headlights, let alone, use the (what seem to me to be) incorrectly named fog lights. Perhaps the Met office need to add a further word for dense fog dependent on even less visibility.

Regional dialects always seem a good place to start when looking for weather words. My suggestion is Mist, Fog (when you can see less than 1km) and Rawky or Roaky (when less than 100 metres). If we called them Rawky Lights, instead of fog lights, we might then not get confused. Or, perhaps people could just look out of the window and decide it would be best in these conditions to make sure their headlights are on! Please.