Pao-Shin Chu takes the long view. While the rest of us only can sit and perspire, cursing today’s humidity, the state climatologist consults his statistics and realizes this kind of suffering has become more common in recent decades.

Hawaii residents once could revel in the knowledge that 200 out of 365 days a year would bring a fresh trade wind breeze from the northeast, Chu said, but now those are on the decline. Trade winds are driven by a subtropical high pressure zone, he added, one that may be weaker or shifted in location.

“Whether this is global warming, I don’t know,” he said, “but this is something we see from data.”

Chu has been professor at the Hawaii Institute of Geophysics at the University of Hawaii since 1985, becoming state climatologist about two decades later.

He’s used to being approached with questions, particularly around weather events such as the beginning of hurricane season. Here’s one answer: Yes, hurricane activity seems to be getting more frequent.

Born in Shanghai and raised in Taiwan, Chu came to the U.S. for his graduate studies, earning both his master’s and doctorate degrees in meteorology at the University of Wisconsin-Madison. His jobs had taken him to Brazil and Oregon before he landed at UH.

Married and the father of two grown sons, Chu enjoys light movie fare at home. That provides respite from the heavy numbers game on the job, where there is still much to be learned about the myriad forces behind climate change.

Making predictions about what the fallout will be is an uncertain business, he said.

“Hopefully, with more and more improvement with the models, techniques and computer resources, we can narrow this kind of uncertainty,” Chu said. “When it comes to the future, we don’t even know what will happen tomorrow.”

QUESTION: How would you explain the difference between meteorology and climatology?

ANSWER: Meteorologists usually deal with day-to-day weather. … For the climatologists, usually we deal with the longer term. Not the day to day but the month to month, the season to season, from year to year. Sometimes even on a climate-change time scale. Very long, sometimes 20 years, 30 years down the road, or even 100 years.

Q: So, in the field you start with meteorology and then advance?

A: That’s a traditional way. You start with some knowledge of meteorology. Then you need to build some knowledge of statistics into the field. You blend meteorology and some statistics into something called climatology. Because climatology is like an average of many, many days, of many, many months. …

Not only the mean, but sometimes also the distribution of the data; sometimes the data is skewed. Not perfect like a bell-shaped curve. …

Q: It’s calculating what’s going on day to day, and what’s going on beneath that? More historical forces?

A: Right. Because sometimes we are interested in a historical event. Like a hurricane here: What happened in the 1950s? In the ’70s? How do they differ from current day’s climate, from current day’s hurricanes, in terms of numbers? In terms of possible tracks? Intensity change? And so on.

Those are the questions for the climatologist. For meteorologists, they just want to know maybe the structure of the hurricane, how the hurricanes formed, where it will be tracked for the next few days, and so on. …

Q: Do you hear critics of climate-change theory say things like, “But it’s snowing outside; there’s no global warming”?

A: You still have the seasonal cycle. Summer is warm, winter is cold. Even though you have climate change, this kind of pattern remains. …

Hawaii, maybe the difference is smaller, but if you live in San Francisco, in Oregon, you can see very significant change.

Q: For Hawaii, when you talk about climate change, what do you see?

A: We’ve seen some decreasing trend in total rainfall … That was the (graph) I showed on my computer screen … That’s the time series of rainfall in Hawaii we’ve produced since the turn of the last century, something like 110 years’ history.

We can see basically for the first 80 years, the change is very slow, not very significant. But since the early 1980s, we do see there is a sharp decrease in rainfall.

Q: Maui has had a drought — it’s more statewide?

A: Drought: I think the recent rain has been helpful, but I think overall, we’re still short of rainfall, particularly on the leeward side …

Q: The leeward side has always been drier, but now it’s drier than it used to be?

A: Yes. Most people live on the leeward side.

Q: So, why is it happening? We’re not the only place, of course.

A: I think California has it even worse, particularly southern California. El Niño just passed … which started in summer of last year. …

Q: Is there a difference in the hurricane seasons, any sort of change in the pattern since you’ve been here?

A: Yeah. I do see in the past that hurricane occurrences were kind of like a rare event. We don’t get many. Iwa was in ‘82. Iniki was in ‘92.

So in year 2002, I run across an engineering professor who also studied hurricanes … He told me, “Pao Shin! You’re a meteorologist?” I said, “Yes?” “You better watch out — this year we’re going to have a hurricane.” I said, “Why?” “We had a hurricane in 1982; we had another in 1992. And now it’s the year 2002; we should have another hurricane.”

I said, “That’s the engineering view. Meteorologists, we don’t look at it that way.” … Nature doesn’t care about this 10-year cycle. …

Q: It’s not like that, then?

A: No — 2002, we didn’t have a hurricane; 2012, we didn’t have a hurricane, right? … There were some hurricanes in the Central Pacific but didn’t cause any damage to the Hawaiian Islands.

Also, their frequency was pretty low. Since 2014, particularly last year, we got many, many hurricanes, right? I think we had eight hurricanes and six tropical storms and one tropical depression. That was a record number.

One time we had three Category 5 hurricanes in the Eastern Pacific, Central Pacific. That was unprecedented … three Category 5 hurricanes simultaneously occur over this year.

Q: Was that a fluke?

A: No, that was not a fluke. A recent study — not my study — showed they expect to see more hurricanes in the future, because of global warming.

Because global warming produces something called a “Pacific meridional mode” — anomalously high temperature … both in the North Pacific and the South Pacific.

This anomalously warm temperature would favor hurricane formations. …

Q: So one would expect this to continue?

A: Yes. So this year so far — last month, July — we also had a record number of storms. …

Q: Used to be usually in the fall when we’d get hurricanes, right?

A: Usually occurs in October, September, not in June or July …

Historically we have maybe four … Last year, we had 15. … 2014 was also high, but not that high. … 2014 was unusual, 2015 was even more unusual.

And now it’s 2016. So far, it looks like we have something going on, maybe another record. I don’t know yet. …

(Pointing to Hawaii on a map) This is 1984. One, two, three, four, five — but none of them reach to Hawaii. Usually to the south, or the north. This is really the sweet spot, in terms of not getting hit by hurricanes.

Q: Why is that? Is it just by chance?

A: Maybe sometimes by chance, but basically, we have a very strong vertical wind shear. Because lower level, you have this eastern trade wind. Upper level, you have a very strong westerly wind.

So you have a very strong wind shear … anything that comes in —

Q: Rips it apart?

A: Rips it apart.

Q: What’s unusual about the ones that do hit? Iniki?

A: Iniki was a special case. … At that time there was an upper-level trough, which moved in right here (near Hawaii). So this trough steered the hurricane moving from the south, northward, just past Kauai.

If the upper-level trough moved a little bit faster, the track would be more on Oahu. Then the damage could be not $2 billion but $20 (billion) or $30 billion, back then.

Q: How do you define your role as state climatologist?

A: State climatologist; basically we collect state data, and we also help answer questions. …

They may ask us, “Would you please help us get rainfall data for September 2011, specific location, specific time?”

Q: For whatever reason?

A: For their research or interest. Sometimes they have to work on some hydrological modeling, sometimes to assess the impact of heavy rainfall on some building damage, or whatever. Sometimes there’s insurance issues. …

Q: Which state agencies?

A: Sometimes Department of Transportation … Department of Health — because sometimes there’s contamination, they want to know if it’s because of heavy rain. …

So the job is very diversified, depending on a person’s need.

Q: In your field, knowing what you know, do you find yourself advocating for climate change policy?

A: As a scientist, I say something when there is support behind it, when there is research. I don’t say, “Blah, blah, there’s no evidence, blah, blah, blah.” I don’t say something like that. I think that’s very dangerous to say. …

If I don’t feel comfortable, I just say, “I don’t know.” I don’t want to advocate for one kind of interest group.

Q: So you don’t offer an opinion about what government should be doing about climate change?

A: I don’t make policy statements. But I think sometimes government agencies listen to us. They are not scientists, right? They are just decision-making, policy-making. But they need the information from scientists.

So we provide information. Whether they use it or not, that’s up to them.