Understanding the typhoon signal system
Hong Kong's tropical-cyclone warning system is famous because the numbers become part of everyday life during a storm. For a visitor, the important point is that the signals describe expected or existing wind conditions in Hong Kong; they are not a simple 1-to-10 severity scale. The active sequence is 1, 3, 8, 9 and 10, with four directional versions of Signal 8.
You should also know that the Tropical Cyclone Warning Signals are only one part of the weather-warning system. Amber, Red and Black Rainstorm Warnings deal with heavy rain; thunderstorm, landslip, strong monsoon and Very Hot Weather warnings cover other hazards. A trip can be badly disrupted by rain even when no high tropical-cyclone signal is in force.
What Signal No. 1 means
Standby Signal No. 1 means a tropical cyclone is centred within about 800 km of Hong Kong and may affect the territory. It is an awareness signal, not a city-shutdown signal. Normal sightseeing may continue, but it is the moment to start paying closer attention to the forecast, especially if you have a hike, boat trip, island ferry, flight or exposed rooftop activity planned.
Do not interpret Signal 1 as "the storm is weak". A powerful cyclone can still be some distance away, and conditions can worsen as its track develops. Check what the Observatory says about expected local winds and the likelihood of higher signals.
What Signal No. 3 means
Strong Wind Signal No. 3 means strong winds are blowing or expected generally near sea level in Hong Kong. The Observatory's published definition uses sustained winds of 41–62 km/h, with gusts potentially much higher. Everyday urban life often continues, but conditions are no longer something to ignore.
Exposed places, beaches, ferries, hiking trails and outdoor attractions can be affected earlier than sheltered city streets. Operators may alter services for their own safety thresholds, so check individual ferry and attraction notices. If you planned a ridge hike or small-boat excursion, choose an indoor alternative rather than waiting for a higher signal to force the decision.
Why there are four Signal No. 8s
Signal No. 8 is the Gale or Storm Signal. There are four versions — 8 NW, 8 SW, 8 NE and 8 SE — indicating the direction from which gale or storm force winds are expected or blowing. HKO's published definition uses sustained winds of 63–117 km/h, with gusts potentially exceeding 180 km/h.
For a visitor, the directional letter matters less than the practical message: serious winds are expected and normal activity changes. The Observatory has, since 1987, used a Pre-No. 8 Special Announcement when it expects Signal 8 within about two hours, giving the public time to get to a safe place.
What happens when Signal No. 8 is issued?
Do not assume there is one universal switch that closes every shop, attraction and transport service at the same second. Schools and many workplaces adopt formal adverse-weather arrangements, while transport operators, ferries, airlines and attractions publish their own service changes. Surface transport and exposed ferry routes may curtail service as winds increase; rail services may operate under modified arrangements.
The practical visitor response is simple: get back to your hotel or another safe indoor place before conditions become severe, not after. Buy any basic food, water or medication you genuinely need early, charge your phone and power bank, secure balcony items if your accommodation has them, and stop making plans that depend on crossing the city.
Signal No. 9: Increasing Gale or Storm
Signal No. 9 means gale or storm force winds are increasing or are expected to increase significantly. By this point you should already be indoors. Stay away from windows and exposed glass, follow hotel or building instructions, and do not go outside to look at the harbour, waves or fallen debris.
The interval between signals is not a countdown clock. Weather systems can strengthen, weaken or change track, and the Observatory bases signals on expected local wind conditions rather than on a fixed time schedule.
Signal No. 10: Hurricane
Hurricane Signal No. 10 is the highest tropical-cyclone warning signal. The Observatory defines it as hurricane-force wind blowing or expected, with sustained winds reaching 118 km/h or above and gusts potentially far higher. It is comparatively rare, but not merely theoretical: Hong Kong issued Signal 10 twice in 2025.
At Signal 10, stay in a secure indoor location and keep well away from windows, glass doors and exposed areas. Do not use a lull in the wind as permission to go outside; the centre or changing structure of a cyclone can produce temporary calmer conditions before dangerous winds return from another direction.
Typhoon signals do not measure a cyclone's category
A common misunderstanding is that "Signal 8" means the storm itself is Category 8 or that "Signal 10" is the cyclone's international strength rating. It does not. Hong Kong's local signal depends on the wind conditions expected in Hong Kong, which are influenced by the storm's intensity, size, track and distance from the territory.
That is why you should follow the local signal and official forecast rather than making decisions based only on whether international reports call the system a tropical storm, typhoon, severe typhoon or super typhoon.
Rainstorm Warnings are a separate system
Hong Kong's Amber, Red and Black Rainstorm Warnings are independent of the tropical-cyclone signals. They can be issued with or without a nearby cyclone. According to the Observatory, the rainy season normally runs from April to September, with particularly heavy and persistent rain possible in May and June.
- Amber: heavy rain has fallen or is expected, with flooding possible in low-lying and poorly drained areas. Treat it as a warning to reassess outdoor plans.
- Red: heavier rain is likely to cause serious road flooding and traffic congestion. Avoid unnecessary travel and follow official advice.
- Black: very heavy rain is causing or threatening major disruption. The Observatory's guidance is to stay indoors or take shelter in a safe place until the heavy rain has passed.
The published hourly rainfall thresholds are at least 30 mm for Amber and 70 mm for Black; warning decisions can also account for prolonged rain. The important visitor takeaway is not to wait for water to be visibly deep around you before changing plans.
Flooding, landslips and trails
Heavy rain can make country-park trails, streams, waterfalls, coastal rocks and steep slopes unsafe very quickly. A tropical-cyclone signal may be low while a rainstorm or landslip warning makes hiking a bad idea. Never enter floodwater, and avoid streams, drainage channels and low-lying paths during intense rain.
If a hiking day falls in unstable weather, use the Observatory forecast and AFCD trail advice together. Postponing the hike is usually far easier than arranging a rescue after conditions deteriorate.
Flights and the airport
Hong Kong International Airport does not operate on a simplistic rule that every flight stops at a particular public signal. Airlines and airport operations respond to actual wind, lightning, ramp conditions, aircraft position and network disruption. A flight can be delayed before Signal 8 or operate after conditions improve while the wider travel network is still recovering.
If severe weather is forecast near your travel day, check your airline's own app or website, keep notifications enabled, and do not travel to the airport purely because the original timetable still shows a departure. If your flight is cancelled, ask the airline about rebooking before separately purchasing an expensive replacement.
Ferries, cruises and island plans
Marine transport is particularly sensitive to wind and sea state. Outlying-island ferries, small-boat tours, junk trips and other marine activities may suspend before city conditions feel especially dramatic. If you are staying on an outlying island and a cyclone is approaching, ask your accommodation and ferry operator about last services well before a higher signal is expected.
Do not treat harbourfront wave watching as entertainment during a strong storm. Storm surge, debris and sudden gusts can make exposed promenades and coastal edges dangerous.
Hotels during a typhoon
Hotels remain the most practical place for most visitors to ride out severe weather. Ask reception about meal arrangements, building-specific safety instructions and whether housekeeping or other services will be reduced. Keep your room key, phone, shoes, medication and a torch or phone light accessible.
Large hotels often have established adverse-weather procedures, but do not assume every restaurant or facility inside the building will operate normally. A small amount of advance planning is useful; panic buying is not.
What to do if a higher signal is forecast
- Check the latest Hong Kong Observatory bulletin, not just the signal icon.
- Cancel exposed outdoor, marine and hiking plans early.
- Return to safe accommodation while transport is still straightforward.
- Charge devices and keep a power bank ready.
- Have water, regular medication and a simple meal or snacks available.
- Move away from windows if winds become severe and follow building instructions.
- Keep monitoring official updates until the warning is lowered and transport operators confirm service.
After the signal is lowered
A lower signal does not mean the city instantly returns to normal. Fallen trees, damaged infrastructure, flooding, landslips, aircraft positioning and transport backlogs can continue to affect plans. Check the exact service you need before leaving your hotel, and give road and ferry networks time to recover.
Trails can remain muddy, unstable or blocked after the urban weather has improved. Avoid making the morning after a major storm your automatic hiking day.
Emergency contacts during severe weather
For a life-threatening or immediate emergency, call 999 for police, fire or ambulance. For general weather information, use the Hong Kong Observatory's website or MyObservatory app. Your hotel is useful for building and neighbourhood information, but official services remain the authority for weather and emergency instructions.