2nd December 2021 – (Hong Kong) With a dry northeast monsoon dominating over southern China for most of the month, November 2021 was marked by dry and sunny weather in Hong Kong. The monthly total sunshine duration amounted to 233.3 hours, about 35 per cent above the normal of 172.3 hours (or about 30 per cent above the 1981-2010 normal of 180.1 hours). The monthly rainfall was only 5.8 millimetres, about 15 per cent of the normal figure of 39.3mm (or about 15 per cent of the 1981-2010 normal of 37.6mm). The accumulated rainfall up to November this year was 2 287.6mm, a deficit of about 5 per cent as compared with the normal of 2,402.4mm (or about 4 per cent below the 1981-2010 normal of 2 371.7mm) for the same period. The monthly mean temperature of 22.4 degrees was near the normal figure of 22.2 degrees (or 0.6 degrees above the 1981-2010 normal figure). Mainly attributed to the exceptionally hot weather in September 2021, the autumn of this year from September to November was much warmer than usual with the mean temperature reaching 26.0 degrees, the third highest on record for the same period.
Under the influence of a fresh to strong easterly airstream, apart from a few light rain patches in the morning from 1st to 3rd November, the weather was generally fine on the first five days of the month. With abundant sunshine and local winds moderating, it was rather warm during the day from 6th to 7th November. The temperature recorded at the Hong Kong Observatory (HKO) rose to a maximum of 29.2 degrees on 6th November, the highest of the month.
A cold front moved across the coastal areas of Guangdong on the morning of 8th November. With winds strengthening from the north and a few rain patches, local temperatures fell significantly in the morning. Under the influence of the associated dry northeast monsoon, the weather turned fine and dry during the day. Dominated by the dry northeast monsoon and the subsequent replenishment, the weather was generally fine and dry from 9th to 18th November. There were cool mornings from 9th to 10th November, and the weather was very dry during the day from 9th to 13th November. The northeast monsoon over the coast of Guangdong was replaced by an easterly airstream on 19th November. Locally, there were a few rain patches in the morning and sunny intervals during the day. Apart from a few rain patches in the morning, the weather turned mainly fine on 20th November. The easterly airstream abated gradually on the next day and there were sunny periods during the day.
Another cold front moved across the coastal areas of Guangdong in the morning of 22nd November. Affected by the northeast monsoon associated with the cold front and a broad cloud band over the South China coast, the weather of Hong Kong became cloudy and cool with a few rain patches from 22nd to 23rd November. The temperature recorded at the HKO dropped to 14.3 degrees in the morning of November 23, the lowest of the month. Under the influence of the dry northeast monsoon and with the thinning out of the cloud band, the weather turned generally fine and dry during the day on 24th November and remained till the end of the month.
One tropical cyclone occurred over the South China Sea and the western North Pacific in November 2021.