Newsletter Issue 63 (January 2026)

「2021-2025十大矚目天氣及氣候事件選舉」網上投票

香港天文台聯同香港氣象學會舉辦《2021-2025十大矚目天氣及氣候事件選舉》，旨在引起公眾關注過去五年在香港及全球發生重大影響的天氣及氣候事件，期望藉此提升公眾對極端天氣與氣候變化的認知及生態環境的關注。
請即投票選出你心目中最具代表性嘅天氣及氣候事件！

The year’s weather 2025 – a stormy 2025

Globally, 2025 is on track to be the second or third warmest years on record according to the WMO’s preliminary assessment. Over the Arctic and the Antarctica, sea-ice extent remained well below average during the year. In particular, the Arctic annual maximum sea-ice extent was the lowest in the satellite record. Extreme weather events affected many parts of the world in 2025, including heatwaves, severe droughts, severe flooding triggered by extreme rainfall and severe damages and heavy casualties inflicted by tropical cyclones.

The weather of December 2025 – An unseasonably mild December

With the northeast monsoon over southern China generally weaker than normal for most of the time in the month, December 2025 was much warmer than usual in Hong Kong. The monthly mean maximum temperature, monthly mean temperature and monthly mean minimum temperature were about 2 degrees above their corresponding normals and all of them were the second highest on record for December. This was also the first time that no Cold Weather Warning was in force in November and December in a year.

WMO confirms 2025 was one of warmest years on record

WMO has confirmed that 2025 was one of the three warmest years on record, continuing the streak of extraordinary global temperatures. The past 11 years have been the 11 warmest on record, and ocean heating continues unabated. “The year 2025 started and ended with a cooling La Niña and yet it was still one of the warmest years on record globally because of the accumulation of heat-trapping greenhouse gases in our atmosphere.” said WMO Secretary-General Celeste Saulo.

Global Seasonal Climate Update for February-March-April 2026

For February–April 2026, below‑average SST anomalies in the central and eastern equatorial Pacific are forecast to weaken, indicating a gradual transition toward ENSO‑neutral conditions. Persistently above‑average SSTs in the western Pacific are expected to maintain a pronounced east–west gradient, continuing to reinforce La Niña‑like atmospheric patterns across the equatorial Pacific.

Four-hour thunderstorm nowcasting using a deep diffusion model for satellite data

Severe storms threaten human lives and cause substantial economic losses. In this work, authors present a storm nowcasting system based on satellite data and AI techniques. It extends forecasts up to 4 h in advance, providing more accurate and detailed predictions of storm growth and decay. Its potential for global application offers an effective means to enhance preparedness and reduce the impact of severe storms worldwide.

The world has entered a new era of ‘water bankruptcy’ with irreversible consequences

The world has entered ‘an era of global water bankruptcy’ with irreversible consequences, according to a new United Nations report. “If you keep calling this situation a crisis, you’re implying that it’s temporary. It’s a shock. We can mitigate it. With bankruptcy, while it’s still vital to fix and mitigate where possible. You also need to adapt to a new reality… to new conditions that are more restrictive than before.”, said by the report’s author, Kaveh Madani.

UK to join major wind farm project with nine European countries

The UK is set to back a vast new fleet of offshore wind projects in the North Sea alongside nine other European countries including Norway, Germany and the Netherlands. The North Sea countries pledged to develop 300 gigawatts (GW) of offshore wind capacity three years ago. This new deal means 100GW of the total will be built jointly. It is expected to say 20GW of that should be under way by 2030.

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