The temperature has been peaking up in the high 70s Fahrenheit for most of the National Holiday week just passed here in China. But it hasn't been peaking there for very long; and the fall-off in temperature at dusk has often been quite dramatic. Even during the day, when the sun is shining and the mercury is quite high, I've sensed a distinct nip in the air, an intimation that we're going to be in for a chilly autumn this year, and perhaps an early onset of winter. And a couple of days ago I noticed that the street snack vendors have started selling roasted chestnuts already. This heralds the approach of winter, just as surely as the first appearance of pineapple sellers in April indicates that spring is transitioning into summer.
There was another even more worrying sign of things to come last night: after a few weeks of clear skies and low humidity, the weather turned clammy and overcast again. The cool mists of autumn I find even more draining - and, often, even more smoggy - than the sweltering humidity of summer. I hadn't realised quite how bad things were when I went out in the early evening, but by the time I was returning, towards 11pm, I found that visibility was down to a couple of hundred yards. And the fog was an unearthly ochre colour. This wasn't just a smog, it was the first of the autumn dust storms. Quite a bad one: this morning, all the lanes and alleys in my neighbourhood have turned brown; everywhere is thoroughly coated in a very fine silt.
And of course, this sort of thing plays hell with the respiratory tract. After 20 minutes or so of walking through this, I was feeling the rasping tickliness in the windpipe that threatens to develop into a permanent cough lasting days or weeks at a time - an unlovely phenomenon that those of us who live here in China's horrendously polluted capital have come to know as the 'Beijing throat'.