TYPHOON WARNING SIGNALS AND SYSTEMS
Many locals rely on the Hong Kong Observatory for regular updates on typhoons, through the website, or on their Apple or Android phones. Another common source of information that is a bit broader across South East Asia is the Tropical Storm Risk tracker. Information on incoming typhoons is easy to find, with all local TV stations showing any warning signals in a box on the top right-hand corner of the screen and newspapers giving updates too. In particular, the Hong Kong Observatory often release new ratings around 7am, 10am and 1pm, so those times are your best bet for the most accurate info.
In terms of the warning signals themselves, Hong Kong has T1, T3, T8, T9, and T10. The other warning signs like T2 and T4 disappeared in the 1970s as they were deemed too confusing. Unlike hurricanes or tropical cyclones, which are measured by storm intensity, typhoons in Hong Kong are measured by proximity and effect on the local territory. The Observatory also releases rain warnings: Amber, Red, and Black. So let's break these down for you.
Amber Rain Warning: Possibilities of flooding in low-lying or poorly drained areas.
Red and Black Rain Warnings: Possibilities of severe flooding, leading to traffic congestion and possible landslides.
T1 (Typhoon Warning Signal One): This signal indicates that a typhoon is within 800km of Hong Kong, which in reality means that the typhoon is within a day or two of Hong Kong, but may not even hit Hong Kong at all. There are no real restrictions, although swimming with young children or weaker swimmers is less advised as there may be strong swells in the water.
T3 (Typhoon Warning Signal Three): This signal indicates the typhoon is getting closer to Hong Kong. You can expect winds of around 41-62 km per hour. Kindergartens will shut down, some shops and businesses will close, buildings close outdoor pools facilities, and some boating activities may be canceled - so check if your junk trip will still be on. These generally occur a dozen times a year and are quite common.
T8 (Typhoon Warning Signal Eight): Now, we're getting into the proper storms, with gale-force winds of 63-117km per hour (and gusts of up to 180km per hour!), and heavy rain. Schools, offices, and shops will close. Flights will be suspended, and public transport and taxis will start to shut down. Once the signal is issued, you have a grace period of about 2 hours in which to get yourself and your family back home, during this time, taxis will still be around but may charge a premium, and the MTR runs a peak schedule to accommodate everyone. These happen around once or twice a year.
T9 and T10 (Typhoon Warning Signals Nine and Ten): These are the most severe warnings with hurricane-force winds of over 118km per hour, gusts of over 220km per hour, and torrential rain. This means that the storm is right over Hong Kong, although they don't happen that often, locals will remember recent examples like Mangkhut in 2018 and Hato in 2017. If you live in a high-rise apartment, you may feel the building sway a little - don't panic! The buildings are designed to do this, and it makes it safer for you in the building. If you live in a more remote village, or on the outlying islands, you may lose power to your home and have restricted road access.