[N.B. my desktop is in for repair at the moment, so I'm using an uncalibrated laptop. If the photographs look like they have a colour cast, that's because they probably do. I'll revisit them if necessary when the desktop comes back.]
At this time of year a meteorological phenomenon known as an "inversion"
can happen, when cold air is trapped by high pressure at ground level
by a layer of warmer air above: typically, this leads to fog and, in
suitable locations, interesting phenomena such as hoarfrost. We've had
such conditions this week, and it's been worth getting out of bed early
Well, almost. The fog was actually rather too dense to get the best out of the hoarfrost, which needs a bit more sparkle from sunlight. In places visibility was down to 25 yards or so, and it was like looking through one of those fine sheets of tissue that used to be bound into a book in order to protect the illustrative plates.