The weather of March 2025 was drier and milder than usual in Hong Kong. The monthly mean relative humidity of 74 percent was 8 percent below the normal of 82 percent and one of the fourth lowest on record for March. The monthly total sunshine duration amounted to 143.8 hours, about 44 percent above the normal of 100.0 hours. With more sunshine, the monthly mean maximum temperature of 23.5 degrees was 1.6 degrees above the normal and one of the tenth highest on record for March. The monthly mean temperature of 20.1 degrees and monthly mean minimum temperature of 17.7 degrees were 0.6 degrees and 0.1 degrees above their corresponding normals. Rainfall in the month was 38.1 millimetres, about 51 percent of the normal of 75.3 millimetres. The accumulated rainfall in the first three months of the year was 68.4 millimetres, about 54 percent below the normal of 147.4 millimetres for the same period.

Affected by a humid maritime airstream, the weather was mainly cloudy and humid with rising temperatures on the first four days of the month. It was foggy on 2 – 4 March. The visibility in many places once fell below 1000 metres on 2 March. A cold front moved across the coast of Guangdong on the night of 4 March. Under the influence of the associated northeast monsoon and a broad band of clouds covering the coast of Guangdong, temperatures fell progressively with a few rain patches on the following three days. More than 10 millimetres of rainfall were recorded over many parts of the territory on 6 March. The temperatures at the Observatory fell to a minimum of 12.1 degrees the next morning, the lowest of the month.

The northeast monsoon over the coast of Guangdong was gradually replaced by a relatively dry easterly airstream on 8 March. While it was mainly cloudy with one or two light rain patches that morning, there were sunny periods that afternoon and in the following two days. With a band of clouds covering the coast of Guangdong, the weather became mainly cloudy on 11 – 12 March with one or two rain patches on 12 March. Winds were weak over the coast of Guangdong on 13 March. Locally, it was hot with sunny periods. With a humid easterly airstream affecting the coast of Guangdong the next day, the weather turned mainly cloudy with one or two light rain patches. Visibility was rather low in some areas and once fell to around 1000 metres in the harbour.

With a trough of low pressure over inland Guangdong developing into a cold front and moving across the coastal areas on 15 March, heavy showers and severe squally thunderstorms ahead of the cold front brought around 20 millimetres of rainfall and violent gusts to many places in Hong Kong that afternoon. Hail was even reported at Tai Po. Under the influence of the associated northeast monsoon, the weather became drier and cooler in the following six days. There were sunny periods on 16 March. Affected by a band of clouds covering southern China, it became cloudier with one or two rain patches on the next two days. With the departure of the band of clouds and the influence of an anticyclone aloft, the weather turned fine and dry on 19 – 25 March. Under the influence of a southerly airstream, the weather became relatively humid with rising temperatures on 26 – 28 March. There were fog patches and the weather was hot on 28 March. The temperatures at the Observatory rose to a maximum of 29.4 degrees that afternoon, the highest of the month. A cold front moved across the coast of southern China that evening and brought a few rain patches and significantly cooler weather to Hong Kong that night and the following two days. Under the persistent influence of the associated northeast monsoon, the last two days of the month remained cold in the morning.

There was no tropical cyclone over the South China Sea and the western North Pacific in March 2025.