2 December 2020

With the northeast monsoon over southern China generally weaker than normal for most of the time in the month, November 2020 was much warmer than usual in Hong Kong. The monthly mean maximum temperature was 26.4 degrees, 2.3 degrees above the normal figure and the highest on record for November. The monthly mean temperature of 23.5 degrees and mean minimum temperature of 21.7 degrees were respectively 1.7 degrees and 1.9 degrees above their corresponding normal figures and both were the second highest on record for November. Moreover, the autumn mean temperature in Hong Kong for the period from September to November 2020 was 25.8 degrees, 0.8 degrees above the normal figure and one of the fourth warmest autumns on record. The month was also drier than usual with a total rainfall of 5.1 millimetres, about 14 percent of the normal figure of 37.6 millimetres. The accumulated rainfall this year up to November was 2393.5 millimetres, slightly more than the normal figure of 2371.7 millimetres for the same period.

Dominated by a dry northeast monsoon, apart from cloudy interludes on 3 and 8 November and a few light rain patches on 3 – 4 November, the weather of Hong Kong was generally fine and dry during the day on the first eight days of the month. With plenty of sunshine, the maximum temperature at the Observatory rose to 30.2 degrees on 7 November, the highest of the month and also the hottest Winter Commences on record. Meanwhile, tropical cyclone Etau moved across the southern part of the South China Sea on 8 - 10 November. Affected by the outer cloud band associated with Etau, local weather turned cloudy with a few light rain patches on the afternoon of 9 November and remained generally cloudy the next day.

Under the influence of the dry northeast monsoon, it was generally fine and dry during the day with slightly cooler mornings on 11 – 12 November. Meanwhile, tropical cyclone Vamco moved across the central part of the South China Sea on 12 - 15 November. Affected by the outer cloud band associated with Vamco, local weather became mainly cloudy with a few light rain patches on 13 – 15 November. Dominated by the anticyclone aloft, sunny weather returned on 16 – 17 November.

Affected by an easterly airstream, local weather became warmer with a few mist and light rain patches on 18 - 19 November. Under light wind conditions, it was cloudy with coastal fog on the morning of 20 November. The visibility at Waglan Island once fell below 200 metres. With the cloud layer thinning out, the weather became sunny and hot in that afternoon. A surge of the northeast monsoon reached the coast of Guangdong on the morning of 21 November. Locally, there was coastal fog at first. The weather turned mainly cloudy and cooler with a few rain patches on that day. While there were a few light rain patches on the morning of 22 November, the weather gradually turned fine during the day.

Under the influence of a replenishment of the northeast monsoon, it was cooler, cloudy with a few light rain patches on 23 November. The clouds gradually thinned out and local weather became generally fine and dry on 24 – 26 November. Affected by another replenishments of the northeast monsoon, the weather became windier with cooler mornings towards the end of the month. The temperature at the Observatory dropped to a minimum of 16.4 degrees on the morning of 30 November, the lowest of the month.

Four tropical cyclones occurred over the South China Sea and the western North Pacific in November 2020.