The Weather of April 2026 - An exceptionally warm April

The exceptionally warm weather in the first quarter of 2026 continued into April 2026, mainly attributed to the warmer-than-normal sea surface temperatures and a stronger-than-usual southerly flow in the lower atmosphere over the northern part of the South China Sea. The monthly mean minimum temperature of 23.8 degrees, mean temperature of 25.5 degrees, and mean maximum temperature of 27.9 degrees were respectively 2.7 degrees, 2.5 degrees, and 2.3 degrees above their corresponding normals. All three values were the second highest on record for April. The monthly rainfall was 160.4 millimetres, about 5 percent above the normal of 153.0 millimetres. The accumulated rainfall recorded for the first four months of the year was 359.6 millimetres, about 20 percent above the normal of 300.4 millimetres for the same period.

Under the influence of the northeast monsoon and a band of clouds covering the coast of Guangdong, local weather was mainly cloudy with a slightly cooler morning on the first day of the month. There were also one or two showers at night. Affected by an easterly airstream and a subsequent southerly airstream, the weather of Hong Kong remained cloudy with a few showers on the next two days. With a trough of low pressure lingering over the coastal areas of Guangdong, there were occasional showers and a few squally thunderstorms on 4 - 5 April. Showers were heavy at times. More than 40 millimetres of rainfall were generally recorded over the eastern part of Hong Kong and rainfall even exceeded 80 millimetres over Tai Po District on these two days. The Observatory registered a daily rainfall of 45.1 millimetres on 5 April, the second highest on record for the Ching Ming Festival since 1884.

As a southerly airstream set in, the weather of Hong Kong became hot with sunny intervals during the day on 6 - 7 April. Under the influence of a strong easterly airstream and associated cloud bands over the coast of Guangdong on 8 April, local weather turned windier and cloudy with a few rain patches. Visibility was relatively low in some areas. With the easterly airstream being replaced by a southerly airstream the following day, local weather was misty with one or two light rain patches in the morning. The visibility in the harbour once fell below 3000 metres in the morning. It was hot with sunny intervals during the day. The southerly airstream continued to affect the coast of Guangdong on 10 - 16 April. Local weather remained mainly cloudy on 10 - 12 April and it was hot during the day. An anticyclone aloft brought sunny periods and hot weather during the day to Hong Kong on 13 - 16 April. With abundant sunshine, the temperature at the Observatory rose to a maximum of 30.2 degrees in the afternoon on 16 April, the highest of the month.

An area of intense thundery showers associated with a trough of low pressure affected the vicinity of the Pearl River Estuary on the afternoon of 17 April. Locally, heavy showers with severe squally thunderstorms were recorded that afternoon, with over 30 millimetres of rainfall on Hong Kong Island and Lantau Island. Hail was reported on Lamma Island. Winds were weak on the next three days. The weather of Hong Kong was mainly fine, hot and dry during the day on 18 - 19 April, then turned mainly cloudy with a few showers on 20 April. Under light wind conditions, visibility was rather low in some areas on 18 April and the mornings of 19 - 20 April. Showers and thunderstorms associated with upper-air disturbances affected the coast of Guangdong on 21 April. Locally, the weather was mainly cloudy with a few showers in the morning. Showers were heavier with squally thunderstorms over the eastern part of Hong Kong Island and Sai Kung District. With the departure of upper-air disturbances, the weather improved on the afternoon of 21 April with sunny intervals. Local weather remained hot with sunny periods during the day on 22 April under the influence of a southerly airstream.

A cold front moved across the coast of Guangdong around noon on 23 April. The associated northeast monsoon brought cooler weather later that day with temperatures generally three to five degrees lower than those of the day before. With the continual influence of the northeast monsoon on the next day, the temperature at the Observatory dropped to a minimum of 19.7 degrees on the afternoon of 24 April, the lowest of the month. Besides, upper-air disturbances also brought showers and squally thunderstorms to the territory on 23 - 24 April. Around 20 millimetres of rainfall were recorded in the New Territories in the evening on 23 April and rainfall exceeded 30 millimetres over many places on 24 April. As the northeast monsoon and a cloud band lingered, local weather was mainly cloudy on 25 April with one or two light rain patches in the morning. A drier easterly airstream affected the coast of Guangdong on the next two days, bringing generally fine and dry weather during the day on 26 - 27 April. Upper-air disturbances affected Guangdong on the next two days. Local weather was mainly cloudy with sunny intervals during the day on 28 April. There were a few showers and isolated thunderstorms in the afternoon. A cold front moved across the coastal areas of Guangdong on the afternoon of 29 April. Locally, it was mainly cloudy with occasional showers and a few squally thunderstorms that day. Showers were heavy at times. Around 30 millimetres of rainfall were recorded over many places, and rainfall even exceeded 50 millimetres over Hong Kong Island. Temperature started to drop in the late afternoon due to the associated northeast monsoon. As the upper-air disturbances departed and under the influence of the northeast monsoon, local weather was dry during the day with sunny intervals on the last day of the month. It was cooler in the morning. The relative humidity over most parts of the territory during the day fell to around 50 percent.

One tropical cyclone occurred over the South China Sea and the western North Pacific in April 2026.