Winter at last?

Yesterday's damp fog was driven away overnight by an area of high pressure, resulting in much the hardest frost we've had so far this year. And today might well have been the first on which the daytime temperature didn't rise above freezing (although, if Weather Underground's Beijing page is to be believed, the mean air temperature did just teeter a few degrees above - but it certainly didn't feel like it with the windchill!).

Walking around the nearby Houhai lakes area this morning (on my way to make a desperate last-minute mailing of Christmas cards at my local post office), I discovered somewhat to my surprise, that this recent drop in temperature had apparently been enough to start the ice freezing on the lake. Most years, I think, the relevant authorities actually drain most of the water out of these lakes at the onset 0f winter (I'm not sure if that does anything to help the formation of ice, or if it just renders things less hazardous if people should happen to fall through the ice), but they don't seem to have done that so far this year. And yet the lakes are freezing anyway - a good and thick-ish covering over all but the very edges of the surface.

This is somewhat of a mystery to me, because I really wouldn't have thought that, until last night, it had been cold enough to make much of a start on this process (the last couple of weeks, it's been really strangely mild for the time of year, and I don't think it's dropped much below freezing even at night). And the old city moat near my apartment doesn't have the slightest suggestion of any ice-formation on it (though perhaps sewage works as a kind of anti-freeze?). I wonder if they're adding something to the lake water to make it freeze? Ice-9, maybe??

I confess I tend not to notice exactly when the icing of the lakes occurs, because my jogging habit fades (a figure-8 circuit of the two main lakes is my favoured route) as the weather gets colder at this time of year, and I rarely go out to any of the lakeshore bars..... so my steps may not take me past there for days or weeks at a time in December. However, I am pretty sure that most of the years I've been living here, the icing has already been pretty much complete by now, and it is some time around the middle of this month that the annual 'frost fair' gets under way - with skating, sledding, and various other amusements taking over the ice until the end of January or beginning of February.

The ice certainly isn't thick enough for that yet - I suspect we're going to be a week or two behind the normal schedule this year. Global warming, anyone?