2 April 2020

With the northeast monsoon over southern China generally weaker than normal for most of the time in the month, March 2020 continued to be much warmer than usual in Hong Kong. The monthly mean temperature of 21.3 degrees and mean minimum temperature of 19.7 degrees were respectively 2.2 degrees and 2.5 degrees above their corresponding normal figures and both were one of the second highest on record for March. The monthly mean maximum temperature was 23.8 degrees, 2.4 degrees above the normal figure and the fifth highest on record for March. The month was also drier than usual with a total rainfall of 41.3 millimetres, about half of the normal figure of 82.2 millimetres. The accumulated rainfall recorded in the first three months of the year was 135.9 millimetres, about 16 percent below the normal figure of 161.3 millimetres for the same period.

Under the influence of a maritime airstream, the weather of Hong Kong was sunny and warm with relatively low visibility on 1 March. With the setting in of a fresh to strong easterly airstream over the coast of Guangdong, the weather turned cloudier with some rain patches and slightly cooler in the next two days. A cold front over southern China moved across the coastal areas of Guangdong on the afternoon of 4 March, bringing more rain to Hong Kong. With the strengthening of the northeast monsoon, the weather became cooler and the temperature at the Observatory fell to a minimum of 16.5 degrees on 5 March, the lowest of the month. This is also the highest monthly absolute minimum temperature on record for March.

Affected by a warm and humid maritime airstream over the coast of Guangdong, the weather in Hong Kong became warm and foggy on 7 – 9 March. Visibility at Waglan Island once fell to around 100 metres on 8 and 9 March. A cold front moved across the south China coast in the small hours on 10 March. Under the influence of the dry northerly winds, local weather became dry with sunny periods during the day. With the setting in of cloud band, the weather turned cloudy and cooler with a few rain patches on 11 – 12 March.

A warm and humid maritime airstream brought foggy weather to Hong Kong on 13 March and the visibility at Waglan Island once fell below 100 metres. A trough of low pressure moved across the south China coastal areas and brought some showers on the morning of 14 March. Under the influence of a relatively dry northeast monsoon, local weather became dry with sunny periods during the day and remained so in the next two days. With the moderation of the northeast monsoon, the weather of Hong Kong turned mainly cloudy on 17 March.

Another trough of low pressure lingering over Guangdong brought showers and thunderstorms to Hong Kong on 18 March with 10 to 20 millimetres of rainfall recorded over most parts of the territory. With the gradual return of a maritime airstream, the weather was humid and misty in the next few days. With plenty of sunshine on 22 and 23 March, the maximum temperature at the Observatory soared to 28.5 degrees on both days, the highest of the month.

The weather was rather warm with sunny periods and a few showers on 24 – 25 March. An upper air disturbance brought a few thundery showers on the morning of 26 March. As the showers subsided, there were sunny intervals in the afternoon and the next day. A cold front moved across the south China coastal areas on the morning of 28 March and brought thundery showers to the local region. Affected by the northeast monsoon, local weather was windy and slightly cooler with a few rain patches in the next two days. It was humid with some rain patches and coastal fog and on the last day of the month. Visibility at Waglan Island stayed around 100 metres in the afternoon.


There was no tropical cyclone over the South China Sea and the western North Pacific in March 2020.

Details of issuance and cancellation of various warnings/signals in the month are summarized in Tables 1.1 to 1.4.  Monthly meteorological figures and departures from normal for March are tabulated in Table 2.