With the northeast monsoon over southern China being generally weaker than normal for most of the time during the month, January 2020 was the warmest January on record in Hong Kong. The mean maximum temperature of 21.2 degrees and the mean temperature of 18.6 degrees were 2.6 degrees and 2.3 degrees above their corresponding normal figures respectively and both were the highest on record for January. The mean minimum temperature of 16.8 degrees was 2.3 degrees above the normal figure and the joint second highest on record for January. The month was also drier than usual with only 14.8 millimetres of rainfall recorded, about 60 per cent of the normal figure of 24.7 mm.
      
     Under the influence of a fresh to strong northeast monsoon, the weather of Hong Kong was windy and cool with a few rain patches on the morning of the first day of the month. With the northeast monsoon moderating, the covering clouds thinned out gradually and the weather became generally fine on the afternoon of January 2. An anticyclone aloft southern China maintained generally fine weather in Hong Kong for the next two days. With the establishment of a ridge of high pressure over southeastern China, local winds strengthened from the east and the weather became mainly cloudy on January 5 and 6. The weather turned generally fine during the day as the winds weakened on January 7.
      
     A surge of the northeast monsoon reached the south China coastal areas on the morning of January 8. The weather of Hong Kong remained fine with winds picking up from the east in the afternoon. With plenty of sunshine, the maximum temperature at the Hong Kong Observatory rose to 26.0 degrees, the highest of the month. Under the influence of the fresh to strong northeast monsoon, local weather was slightly cooler with sunny periods on January 9 and 10. With winds subsiding, visibility over many areas was relatively low during the day on January 11. A cold front over southern China moved across the coastal areas of Guangdong that evening, bringing cooler mornings to Hong Kong for the next two days.
      
     Under the influence of an easterly airstream, the weather of Hong Kong became fine during the day on January 14. With the strengthening of the easterly airstream, local weather turned mainly cloudy with a few rain patches during the next two days. Meanwhile, a cold front moved across the coastal areas of Guangdong on the night of January 16. The associated northeast monsoon brought mainly cloudy weather and cool mornings to Hong Kong from January 17 to 21. With the northeast monsoon being replaced by a maritime airstream, local weather became milder with a few light rain patches and coastal mist or fog from January 22 to 24. The visibility on the morning of January 24 dropped to around 100 metres at Waglan Island. Affected by rainbands over the south China coast, it was mainly cloudy with a few rain patches in Hong Kong on January 25.
      
     As a cold front moved across the coastal areas of Guangdong on the night of January 25, the weather of Hong Kong became mainly cloudy with occasional rain and thunderstorms on January 26 with about 10 mm of rainfall recorded over many places that morning. The associated intense winter monsoon also brought appreciably cooler weather to the territory on that day. With the northerlies prevailing, it was mainly cloudy and cold with a few rain patches on January 27 and on the morning of January 28. The weather then turned fine and dry on January 28 as the clouds dissipated gradually during the day. The temperatures at the Hong Kong Observatory fell to a minimum of 10.8 degrees on the morning of January 28, the lowest of the month. Affected by the winter monsoon, local weather remained generally fine and dry with cold mornings till the end of the month.
      
     There was no tropical cyclone over the South China Sea and the western North Pacific in January 2020.
      
     Details of issuances and cancellations of various warnings/signals in January are summarised in Table 1. Monthly meteorological figures and departures from normal for January are tabulated in Table 2.

Ends/Tuesday, February 4, 2020
Issued at HKT 16:38

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