Despite mildness and wetness being a common factor, there are a number
of subtle differences between this spell and that of Nov/Dec. The most
notable one is amount of sun - the previous spell was actually quite
sunny, with a general "if it's not raining, it's sunny" rule. It also
had a number of clear and consequently coldish (though no frost)
evenings. Sun is very much at a premium in the current spell, by
contrast, the last four days in the Southampton area having perhaps a
couple of hours of sun at best, with only one clear evening (Friday) -
the supposed polar spells between the fronts being overcast from
non-descript cumulus/stratus hybrid stuff. It was also less mild
relative to normal.

Ironically the wind was more southwesterly than now, and generally,
IMX, (in southern England anyhow) southwesterlies are cloudier and less
mild than straight westerlies. Also ironically, the November spell was
more cyclonic, and again, cloudiness tends to increase the closer to
the centre of a low you are.

I'm guessing it might be something to do with the time of year. In
November, we're still quite close to the autumn equinox, whilst in
January there's been several months of short days with limited scope
for the sun to evaporate dampness in the atmosphere - hence the damp
has "built up". Is this correct?

Nick