The Weather of October 2025 - The warmest October

With a stronger than normal upper-air anticyclone covering southern China and cooler air from the north only reaching the coast of southern China later in the month, October 2025 was exceptionally warm in Hong Kong. The monthly mean temperature of 27.4 degrees and monthly mean minimum temperature of 25.6 degrees were both the highest on record for October. Moreover, the monthly mean maximum temperature of 29.9 degrees was the second highest on record. There were also in total 7 hot nights including 4 consecutive hot nights that started from 16 October, and 4 very hot days in the month, all breaking the records for October. The month was also much drier than usual with a total rainfall of 31.2 millimetres, only about 26 percent of the normal of 120.3 millimetres. The accumulated rainfall this year up to October was 2545.2 millimetres, about 8 percent above the normal of 2363.1 millimetres for the same period.

Under the influence of an anticyclone aloft, the local weather was generally fine and very hot on the first three days of the month. The maximum temperature at the Observatory rose to 33.6 degrees on the afternoon of 1 October, the highest of the month. Besides, Matmo formed as a tropical depression over the seas east of the Philippines on 1 October. It moved west-northwestwards across Luzon, edged closer to the coast of Guangdong and progressively intensified into a typhoon in the following three days. Matmo made landfall over Leizhou Peninsula on the afternoon of 5 October. It then moved across the inland areas of Guangxi and the northern part of Vietnam and progressively weakened into an area of low pressure in the next two days. Locally, the weather remained mainly fine at first and very hot on 4 October. With the approach of Matmo, local winds strengthened in the afternoon. Winds were generally strong, once reaching gale force offshore and on high ground that afternoon and the next day. The weather turned cloudy with a few squally showers and violent gusts. There were also thunderstorms on 4 October. More than 10 millimetres of rainfall were recorded over many places, and rainfall even exceeded 40 millimetres over parts of Lantau Island on 5 October. Although it was mainly cloudy with one or two showers at first the next day, there were sunny intervals during the day as Matmo departed.

Dominated by an anticyclone aloft, apart from a few showers, it was generally fine and very hot on 7 - 11 October. The maximum temperature at the Observatory rose to 33.1 degrees on 8 October, the hottest Cold Dew on record. With a broad trough of low pressure edging closer to the coast of Guangdong, the weather of Hong Kong turned mainly cloudy with showers and thunderstorms on 12 October, with more than 20 millimetres recorded over Lantau Island and Hong Kong Island. A waterspout was also spotted near Lamma Island in the afternoon. The broad tough of low pressure continued to affect the coast of Guangdong in the next two days. Locally, there were showers and thunderstorms on the morning of 14 October, with more than 20 millimetres recorded over parts of the northern New Territories. With the anticyclone aloft strengthening again over southern China, apart from a few showers, the local weather turned generally fine on the afternoon of 14 October and remained so in the following five days. It was very hot on 18 - 19 October. The minimum temperature recorded at the Observatory on 19 October was 28.2 degrees, making it the latest hot night of a year on record.

Besides, Fengshen formed as a tropical depression over the seas east of the Philippines on the morning of 17 October. It then tracked generally west-northwestwards across the central part of the Philippines and entered the central part of the South China Sea in the following two days. It intensified into a severe tropical storm and edged closer to the coast of Guangdong on 20 October. It turned to move west-southwestwards across the seas south of Hainan Island and weakened progressively in the next three days. Meanwhile, an intense northeast monsoon affected southern China on 20 October. Locally, winds were strong offshore. Under the combined effect of Fengshen and the intense northeast monsoon, the local winds were generally strong on 21 October, and occasionally reaching gale force on high ground. The outer rainbands of Fengshen also brought cloudy weather and a few rain patches to the territory. It was appreciably cooler on 22 October, with temperatures over most parts of the territory in the afternoon around 15 degrees lower than those on 19 October. Besides, temperature at the Observatory fell to a minimum of 18.2 degrees on 22 October, the lowest of the month. Under the continuous influence of the monsoon and a broad band of clouds covering southern China, the weather remained generally cloudy with a few rain patches in the following six days. With the band of clouds thinning out, there were sunny periods on 25 - 26 October. Affected by an easterly airstream, it was mainly cloudy with one or two rain patches on 29 - 30 October. With the moderation of the easterly airstream, there were sunny periods on the last day of the month.

Four tropical cyclones occurred over the South China Sea and the western North Pacific in October 2025.