Leung Wing Mo, former assistant director of the Hong Kong Observatory, is on Straight Talk this week. He is here to talk about the advancement of weather forecasting and how we can forecast more accurately. Leung also talks about how climate change is affecting everyone and what we do.

Check out the full transcript of TVB’s Straight Talk host Eugene Chan Kin-keung’s interview with Leung Wing-mo:

Chan: Welcome to Straight Talk! I'm Eugene Chan. This evening, we are tackling a topic that affects every one of us in Hong Kong: extreme weather risk. And joining us is a true authority on the subject, Leung Wing-mo, former assistant director of the Hong Kong Observatory. He is an active advisor on environmental and climate change issues in Hong Kong, and has helped formulate the long-term decarbonization strategy in our city. Leung is currently an Adjunct Professor of both the Hong Kong Polytechnic University and the Chinese University of Hong Kong. To many Hong Kong viewers, he is a familiar and trusted face, being the first professional meteorologist here to host TV weather programs and more recently, the host of over 400 episodes of the popular science series, “MObservatory”, on TVB. Welcome, Wing-mo!

Leung: Thank you, Eugene, for having me for the 1st program of 2026. It’s an honor and a privilege.

Chan: And I'm sure the viewers are very happy to see you back on stage, because you hold a very popular show that everybody learns from.

Leung: Thank you.

Weather forecasting

Chan: Let's start with some basics. I mean, most people check the weather. We only look at the temperature and all that. It looks straightforward. But I would like to know before going into details how difficult it is from your point of view as a forecaster of all these years. Maybe you can take us behind the scenes. I mean, what's actually happening every day?

Leung: Well, weather forecasting is as old as human civilization. You know, thousands and thousands of years ago, our ancestors looked at the sky, looked at the clouds, and tried to find out what kind of weather would become. And it's not, probably, until 100 years ago that we started what we call the objective weather forecasting, because the movement of air in the atmosphere actually can be calculated using equations. But unfortunately, those equations are really very complicated. So, it's not until the advance of a computer that we can realistically forecast the weather. That's in the 1970s and 1960s. Now, in addition to using computer to forecast the weather, using numerical methods or mathematical equations, we have AI, so everybody is talking about AI. It really helps. It really helps. We can see that. Actually, the Observatory has improved the accuracy of the weather forecast by applying AI technology.

Chan: Right, and I'm sure many viewers, when they sort of watch TVB's weather forecasts, they see temperature, relative humidity, sometimes the wind speed, et cetera.

Leung: Wind speed and direction.

Chan: So, what are the figures that we have to look at? I mean, obviously, when you say it's going to be like, 14 degrees or 13 degrees currently, then you are going to put on more clothes. But how about other indicators, how would you use them to make us have a better life in being a citizen in Hong Kong?

Leung: I think, normally, for a normal weather forecast or common weather forecast, we have roughly four parameters – the temperature range, the state of the sky, whether it’s cloudy, or clear, the relative humidity, and also the wind speed and wind direction. Normally, Hong Kong's weather is pretty friendly, so to speak, to us. But there are extreme cases too. So, what we need to really be very focused on the weather forecast is in extreme situations.

Chan: I see.

Leung: Like in very hot days, in very dry days. For example, we have the tragedy of the fire in Tai Po. As a matter of fact, the Hong Kong Observatory has issued the Red Fire Danger Warning more than two days ago. So, it is Red Fire Danger Warning several days in a row. If you are sensitive or you are aware of the danger associated with dry conditions, then hopefully you will pay more attention to preventing the fire and that could perhaps avoid the tragedy. So, for every forecast, most of the citizens are not really concerned, but we should be really concerned about the warnings.

Chan: Right. I mean, Wing-mo, other indicators come to my mind, called a windchill factor, especially when you're in North America, like Canada. Is that relevant in Hong Kong?

Leung: It is. As a matter of fact, last week, we had a surge of the winter monsoon. During the first day, the temperature dropped to around 12 degrees, and the second day around 11 degrees. The main difference, whether you feel chilly or cold or not, is actually the wind speed. So, the first day, you feel actually rather cold, because with the arrival of the cold air, usually the wind speed is stronger. So, you feel somewhat colder. But unfortunately, people in Hong Kong are not accustomed to this kind of concept.

Chan: Right.

Leung: So despite the fact that the Hong Kong Observatory has all those data in the website, not a lot of people pay attention to it.

Chan: Okay. So, I'm sure the viewers will start looking at that.

Leung: Right.

Chan: Number one, making sure if it's a Red Fire Warning; number two, all the wind chill factors. Another area, I'm sure all the viewers know, would definitely be sort of eyeing on the Hong Kong Observatory, is during the tropical typhoon period.

Leung: Definitely.

Chan: So, we have different type of signals over the years. You have changed from one, three, five, six, seven, eight, nine, 10 to one, three, eight, 10 now.

Leung: Nine and 10.

Chan: Nine and 10. Sorry.

Leung: I know, right.

Chan: Before you go into details what go through a forecaster’s mind, every time before you issue this warning, do you have specific parameters? Or it’s based on your experience, or gut feeling?

Leung: Well, as I said, we are now into a stage of objective weather forecasting. So, we can actually use the computer to grind out the equations so that the main objective is to find out what kind of wind speed are we expecting with the approach of a typhoon. It is the wind speed, that is the determining factor. So, if we are expecting strong wind speed, then we might need a number three signal, and number eight signal, and perhaps number 10 signal, if it's a direct hit, or very close to Hong Kong. What we do in the Hong Kong Observatory is, first of all, we forecast a track of the typhoon, or tropical cyclone. Because one factor, which affects wind speed in Hong Kong, is its distance from Hong Kong, when it is closest to us.

Chan: I see.

Leung: So, the track is very important. And then the other factor is how the intensity of the typhoon will change during the course of its movement, because sometimes it will intensify rapidly, like the number 10 signal we had with Ragasa. It’s a very, very strong typhoon, a super typhoon. So, we need to forecast the intensity. By knowing the track and by knowing the intensity, we can pretty sure, quite sure, finding out the kind of wind speed we expect in the next several hours, maybe in the next 24 hours.

Chan: Right, Wing-mo, I think with every job, there's some stress associated with it. As you know, Hong Kong citizens have high expectation of everything, especially from the government. Will you say getting the forecast not so accurate is more stressful, or the time to decide when they issue the warning? How do you feel being on that post before?

Leung: Well, as a matter of fact, I was lucky for not being the one who makes the final decision. You know, the final decision, always rest with the director.

Chan: Right.

Leung: So, I was an assistant director, so I didn't have to shoulder that responsibility. But it's actually, as the first Chinese director of a Hong Kong Observatory said, hoisting typhoon signals or issuing warnings, etc, is both a science and an art. Science, because we have to know, we have to calculate, estimate the wind speed and rainfall and so on. Art, because there is always uncertainty, right? Even with the advance of technology and science, we can never, I can definitely say, we can never put up a warning or put up a forecast, which is 100 percent correct. No, we can't. This is the intrinsic property of the atmosphere. Because of the uncertainty, we have to juggle around with the possibility of our forecast being wrong, and how the citizens are going to receive, or the reception aspect. So, that's why the first Chinese director said that it's also art.

Chan: Right.

Leung: Because of the balance, the kind of uncertainty, and the expectation of the general public.

Chan: Wing-mo, I think there's a very long time Chinese saying that winds and clouds are inherently unpredictable.

Leung: Yes. Even today, yes.

Chan: A lot of viewers will say the Hong Kong Observatory should have known better. Is that a fair expectation?

Leung: It is, of course. Otherwise, how do we justify the existence of the Hong Kong Observatory? We have all the technologies, we have all the techniques and tools and so on. We have all the experience. So, we are obviously in a better position to master the change of weather conditions than anyone else in Hong Kong.

Chan: Right. And also, if you look at, from ancient times, you start looking at the weather and then we have seen AI now … which is the latest development? Would you say that it's easier to predict before, or now? Or I'd rather say, is it more dangerous now, if you get it wrong today, especially with extreme weather?

Leung: No, I would think that it's easier for the forecaster, to forecast the weather, and also to issue a certain kind of warning. But at the same time, life is made more difficult, because the forecaster nowadays has to look into an immense range of information. So, we are talking not just one computer model, not just one AI model. We are talking about probably 6, 7, 8, 9, 10 different models. They have different forecasts. So, the job of the forecaster will be made very difficult to determine which model, which output of the model should we place a more heavier weight? So, that is a judgment.

Chan: Okay.

Leung: Even in this time and date, we still … in the final analysis, it is still a matter of judgment, subjective judgment. But with the help of objective forecasting tools.

Chan: Wing-mo, time for a short break now, we'll be back with more Straight Talk.

Chan: We are back on Straight Talk with Leung Wing-mo, former assistant director of the Hong Kong Observatory, talking about what is involved in weather forecasting and navigating extreme weather. So, Wing-mo, I think the last statement you made before the break was, with AI and then a lot of information, now the forecaster will be able to more accurately predict the weather. And I must say that in a recent typhoon number 10, the signal that we had, Hong Kong had relatively, sort of less damage as compared to before.

Leung: Right.

Chan: So, it definitely plays a very important role, doesn't it?

Leung: Right, right, definitely, because with more accurate forecasts, we can issue the warning a little bit in advance, so that the general public has more time to make preparation, in particular, those vulnerable industries, for example, scaffoldings and things like that, things that are easily affected by typhoons.

Escalating risks

Chan: Since you mentioned typhoons, so-called extreme weather, does it become more frequent now, or are they sort of more intense? It's just a general feeling. Am I correct? If this is correct, what is driving this trend?

Leung: Definitely, we are seeing more and more extreme weather, but we have a whole range of extreme weather. Talk, for example, temperature. Now we don't worry too much about cold weather. Because the number of cold days has dropped drastically. But the number of hot days in particular, the very hot days, has risen very sharply.

Chan: I see.

Leung: For example, in last year, 2025, we had 53 very hot days, in one single year.

Chan: Just over one month, nearly two months.

Leung: Nearly two months. But in my days, in my old days, it was about 10, 12, or 13. So, you are talking about four or five times more very hot days. Now, most of us think that hot weather is just a nuisance. But as a matter of fact, it is a silent killer.

Chan: Really?

Leung: Because there was a study by the Hong Kong University a couple of years ago that because of hot weather, the number of people who died, resulting from hot weather, ranges from about 100 to up to 300 every year.

Chan: That’s a lot.

Leung: That's a lot, because if you take, for instance, we had Ragasa, number 10, last year. We had zero fatality; no one was killed. But for very hot weather, hundreds of people were killed. Of course, they are not just due to heat strokes. It is because it can be a trigger for respiratory illness. It can be a trigger for coronary or heart disease and things like that.

Chan: That means all those citizens who go for outdoor sports, especially even trail walking.

Leung: Yes.

Chan: Say playing golf. Even playing anything outdoor basketball.

Leung: Right, right.

Chan: They should be very careful.

Leung: Yes, also, at the same time, with very hot weather, it tends to be that the air pollution is really bad, under very hot weather conditions. So, it's kind of a perfect storm for someone who has some diseases to pass away.

Chan: So we must be …

Leung: We must be very careful. In particular, the old age people, because, like me …

Chan: You’re far from it.

Leung: … the blood vessels are more or less, I mean, not so elastic, and it's kind of restricted, and things like that.

Chan: I see. Wow, I mean, that's something that we must look at.

Leung: Yes, yes.

Chan: And even, I mean, I just remember, since you mentioned all these typhoons, I remember, we had some people actually going to, so-called, a storm chaser, or they look at the waves. I mean, what are your views on those?

Leung: Well, my view is kind of mixed feeling, actually. There are lots of people who go to the coast simply for the sake of getting excited. Then I think that is really irresponsible, because it's not just the lives of those people that are involved. It's also the lives of policemen and firemen, in case they … you know, last year, during Ragasa, we had some tremendous overtopping waves.

Chan: Yes.

Leung: Waves that are tens of meters, right? That can actually carry the people along the coast into the water, and then you have to ask the policemen and firemen to save them. So, for those people, they are very irresponsible, and then, I think, some kind of punishment should be imposed.

Chan: Well, I think the security chief … yes ...

Leung: But on the other hand ...

Chan: Yes.

Leung: There are people who are genuinely trying to get information from a scientific point of view, and if we are kind of rigid in legislating this kind of laws and so on, then you will restrict the kind of academic or knowledge chasing kind of activities, which, I think, is not really desirable.

Chan: Right. The security chief, Chris Tang, actually has said that those people who are quite irresponsible, especially with the young children.

Leung: Right, particularly.

Chan: Then, they will be charged with child neglect …

Leung: Which I think I totally agree with.

Chan: … but one has to be aware of the other side, where academic pursuant is also something that we have to be encouraged.

Leung: Because I know a lot of storm chasers, who are not just ignorant people, who know about the movement of the typhoon, who expect the winds to be, how strong or whatever, and they are fully equipped, when they go out to take the data and information.

Chan: Right, I see.

Leung: So, I think we should be very careful in legislating these kinds of laws.

Chan: And I think it just comes to my mind, apart from a typhoon, actually, what we call those black rainstorms that we had. I mean, we had, like, five within two weeks, and we had such a sort of severe flooding last September.

Leung: Yes.

Chan: And also, when the MTR was nearly submerged, and whereas they had to evacuate. Was that one off time, or shall we expect even more to come in?

Leung: No, we were definitely going to see more and more of this kind of heavy rainfall event. The reason is simple: climate change and global warming. You see, with the atmosphere getting warmer and warmer, the atmosphere can hold more water vapor. And also, at the same time, with the warmer oceans, the evaporation rate is faster. So, this is a recipe for more heavy rainfall in the future. So, it is kind of surprising that we have five black rainstorm warnings within two weeks. It's totally unexpected, because when we designed this rainstorm, colored rainstorm warning system in 1992, we expected only one black rainstorm warning every year.

Chan: Right.

Leung: Last year, we had five. So, this is totally unexpected.

Chan: Right.

Leung: But that's going to be the trend.

Chan: I mean, thank you very much for that information. I hope the viewers will start to realize weather is a lot more important than we anticipate. You should say the heat, we're going to be careful. Even with waves, you don't want to get by the shore.

Leung: Sure.

Chan: Rainstorms. And also, you have all this flooding and everything can be dangerous. And you also mentioned the Tai Po fire as well. So, there must be some solution to this. I think carbon emissions is something that we talk about all the time. And can you explain how this is linked to climate change?

What’s the solution?

Leung: Well, carbon emission is, I mean, according to physical laws, if we have more carbon dioxide in the atmosphere, which is what we call the greenhouse gases, it will absorb the heat radiation emitting from the Earth to outer space, and then redirect it back to the Earth. So, we get an extra source of heat energy. That's why we have global warming. So the solution is very clear: we have to cut down on carbon dioxide emission. That's why in China, we have the dual carbon goal. Reducing, I mean, reaching the peak in 2030, and then reaching carbon neutrality by 2060.

Chan: Wing-mo, I think I'd have to read this for the viewers' sake: the SAR government has set the goal of carbon neutrality before 2050, and to reduce our carbon emissions by 50 percent by 2035. That's Hong Kong. This is in line to the nation's pledge you just said. Are we on track, actually, for this meaningful progress?

Leung: Yes, I think we are on track. Actually, we have been doing pretty good. You know, in the old days, 10, 20 years ago, the average carbon emission for an average person in Hong Kong was more than 6 tonnes. Now it's around 4 tonnes. So, we have made a lot of progress. But, to me, I think that, I mean, thanks to the government officials, Environmental Protection Department and policy, and so on. To me, I think that we have taken what we call the low hanging fruit.

Chan: Okay.

Leung: Because there are solutions and policies which are easily implemented. For example, for power companies, we change burning coal to burning natural gas, which immediately cuts down the carbon dioxide emission to half.

Chan: Right.

Leung: Right? So, this kind of policy, which can be rather easily implemented using money. But then the rest of the trajectory is going to be very challenging. So, in that aspect, I think every one of us, not just the government, has to take part to …

Chan: Okay, Wing-mo, one last question, we’re running out of time. President Trump has been a critic of all these climate changes and not doing anything. Is that a worrying factor?

Leung: Oh, that's definitely a worrying factor, because there are some organizations which count the number of actions by the Trump administration, which is hurting scientific progress. So, I mean …

Chan: It's going to be something we have to be aware of. Right, right. So, Wing-mo, I'm afraid we have to leave it there, and thank you for your valuable insights into the extreme weather we have been experiencing.

Today's conversation reinforces what we all know. In Chinese, “Heaven holds unpredictable storms”. In our era that unpredictability is growing, but thankfully so is our knowledge and our capacity to prepare. Let's heed those warnings, support smart policies and build a Hong Kong that can weather any storm.

Have a good evening and see you next week.