Hong Kong residents should prepare for a sudden, dramatic plunge in temperatures next week as a reinforcing wave of the powerful northeast monsoon descends upon the region, bringing with it strong winds, exceptionally dry conditions, and the season’s lowest readings. Following a warm start to the weekend, temperatures are forecast to drop by a massive 12 degrees Celsius overnight on Monday, prompting the activation of high-wind alerts and likely triggering a Cold Weather Warning for many districts as conditions turn frigid mid-week.
Temperature Plunge Marks Onset of Winter Conditions
The Hong Kong Observatory forecasts that the current mild conditions along the south China coast will be swiftly replaced by cold, dry air. Monday afternoon is expected to see urban temperatures peak around 27°C; however, a significant reinforcement of the northeast monsoon is predicted to arrive in Guangdong on Monday night. This influx of cold air will cause temperatures in Hong Kong to plummet to approximately 15°C by early Tuesday—a sharp 12-degree drop that constitutes the lowest temperature recorded so far this season.
By Tuesday, strong northerly winds are expected to strengthen significantly, reaching force 6 and peaking at force 7 in offshore and elevated areas throughout Tuesday and Wednesday. These conditions meet the threshold for the Observatory to likely issue the Strong Monsoon Signal, cautioning mariners and residents about high winds.
Tuesday will remain markedly cooler and cloudy, with city temperatures staying between 15°C and 21°C. Automated district forecasts indicate that many areas will register lows near 15°C, with some inland districts, such as Ta Kwu Ling, potentially reaching 13°C.
Cold Weather Warning Criteria Expected Midweek
The cold snap intensifies on Wednesday. Forecasts predict urban areas will see temperatures hover between 13°C and 15°C, with the Tsim Sha Tsui headquarters anticipated to register 13°C. Crucially, many outer and New Territories districts are expected to meet the stringent criteria for a Cold Weather Warning, defined as 12°C or below.
Minimum temperatures of 12°C are projected for districts including Tseung Kwan O, Sha Tin, Tai Po, Sheung Shui, and Tin Shui Wai. The coldest readings are expected in higher-altitude or inland spots like Ta Kwu Ling and Shek Kong, which are forecast to bottom out at 11°C.
Accompanying the cold air will be extremely dry conditions. Relative humidity is expected to drop sharply from Wednesday, settling generally between a low 35% and 60% through midweek. This extended period of very dry air requires residents to take precautions against fire risks and dehydration.
Weekend Weather Prepares for the Shift
Before the monsoon surge, weekend conditions will be mild but breezy. Saturday offers mostly cloudy skies with dry, sunny periods and temperatures ranging from 21°C to 25°C, accompanied by easterly to northeasterly winds reaching force 4 to 5. Sunday is expected to be generally fine and dry, with highs around 26°C. The warm-up culminates momentarily on Monday morning, with urban temperatures hitting 27°C, before cloud cover increases and the dramatic cooling initiates in the evening.
Looking ahead, the intense cold is not expected to persist indefinitely. As the monsoon gradually eases late next week, daytime temperatures are forecast to slowly recover, climbing back to approximately 23°C to 24°C as the following weekend approaches.
Key Takeaways for Residents:
- Prepare for Rapid Cooling: Ensure warm clothing is accessible immediately, particularly for Monday night.
- Monitor Wind Alerts: Those planning outdoor or marine activities should heed the likely Strong Monsoon Signal.
- Stay Hydrated: Extremely low humidity necessitates extra precautions against dry skin and respiratory irritation.
- Check Local District Forecasts: Inland and New Territories areas will experience significantly colder temperatures than urban centers.