IT'S an old joke that the official weatherman can't predict the weather and doesn't know if it's snowing outside. But a flurry of young amateur meteorologists is hailed for usually getting it right, including the Weather God and Dragon King. Li Anlan and Wang Pengpeng report.

For years Chinese people have relied on official weather forecasts by meteorological bureaus to find out if they should wear an overcoat, shed a sweater or carry an umbrella.

The daily weather forecast on China Central Television wins top ratings, but now DIY weathermen have stuck their heads in the clouds and are winning followers for their clear language and spot-on predictions.

Quite a few are doing daily nationwide forecasts online and the local Dragon King contributes to World Expo 2010 forecasts and area micro predictions for the 5.8-square-kilometer Expo site.

Amateur weathermen usually learn how to read charts and data from the Internet. There are several big meteorological forums in China, including Typhoon BBS, one of the earliest and most popular. It contains sections on tropical cyclones, meteorology and weather phenomenon.

Visitors can find not only the latest forecast but also extensive comparative information on temperature, humidity, rainfall and other elements in past years.

The Chinese mainland's official weather Websites contain little comparative information and generally only post basic images and daily information, so it's difficult to acquire past records.

Meteorology fans collect current and past data from many other sources, such as satellite images and the weather bureau in Hong Kong that has long-standing open records. They create a database so everyone has access, and save records in their own computers.

They share their predictions and analysis, showing that forecasting is not just for scientists.

Shanghai Daily talks to two local weathermen: Huatenglongxin (online ID), known as Meteorological Di, or Weather God, real name Chen Wenhui; and the famous Dragon King (Long Wang), Wang Tianlong, a Fudan University student famed for accuracy.

Wang produces a daily online Dragon King Forecast column on "Good Morning, Expo," a student-run newsletter for Expo student volunteers.

Weather God

Chen graduated in 2004 with a major in computer science and now is an IT professional. The weather is his passion, along with geography and travel, and his e-pals call him Meteorological Di or Weather God.

Chen started to post forecasts and analysis four years ago on a forum and now posts regular forecasts and analysis on KDS, a major online society in Shanghai. Most of his posts are about Shanghai.

"It's an interest and doesn't take a lot of time," Chen says. "Usually I need 15 minutes to read diagrams and data and do the forecast."

His language is simple and direct, no jargon, his posts are short - that sets him apart from official weather folks. He's also topical.

For example, he wrote on May 2 that May 7 would be the best day in early May to visit the Expo because the temperature wouldn't exceed 26 degrees Celsius.

He was right. It didn't.

He also said the cooler weather from May 29 to June 3 rarely happened in the past 25 years; he compared data from 2000 to 2009, and found the average temperature this year was 3.5 degrees lower.

Dragon King

In Chinese mythology, Long Wang, or the Dragon King, is a dragon-like god governing waters and rainfall. In reality, Shanghai has its own Dragon King whose forecast accuracy is said to be around 90 percent, sometimes better than the official predictions, and often more detailed.

"Dragon King" Wang posts on Renren.com, a social networking site popular among college students. He posts once or twice a day and now has more than 900 posts on his Webpage, each drawing numerous fans who swear by him.

Wang is an optics and engineering junior at Fudan University.

"It's a habit," says Wang who started posting in September 2008. But he was already forecasting when he was in high school and many classmates consulted him about the weather.

Tested in an interview about the next day's weather, Wang replied without hesitation, "It will be cloudy. The temperature will be similar to today's, from about 18 to 25 or 26 degrees." He turned out to be right. He explained it was caused mainly by high pressure system in Zhejiang Province.

His forecasts and explanations are usually clear and simple.

As an introverted boy, Wang was fascinated by the sky and the clouds and immersed himself in the magic of the heavens. He started to follow the weather forecasts and read many meteorology books and historical data during junior high school.

Wang studied further in high school and was caught up in the study of cloud formations and many phenomenon. When the National College Entrance Exam approached, he had to confine his passion to weekends.

Nowadays it's his daily routine to read satellite images, radargrams and surface weather charts - and even observe the sky.

"Once I did not go to bed until I observed the snow that I had forecast," he recalls. "I went out to check if it was pure snow or sleet. I traveled across many districts to collect and check data."

Since the World Expo Shanghai opened on May 1, Wang has become famous for his daily Dragon King Forecast column on "Good Morning, Expo," a student-run online newsletter for Expo volunteers from Fudan University.

For each day of their 16-day stints, the 2,000 university volunteers receive Wang's forecast at 8am about the weather in each area of the Expo site and different districts in Shanghai.

Many volunteers say his forecasts are more detailed and practical than the official one and they missed his updates when their volunteer terms ended.

A volunteer himself, Wang wasn't able to write after his afternoon shift to meet the evening deadline. So he condensed his work and developed a three-day procedure for each column, involving research, observations and updates by text message to get it exactly right.

"Together with my posts on Renren.com, it took me about two hours every day," he says. "I really enjoy the process of study and forecasting and I'm interested in not only short-term phenomena but also long-term climate change.

"I'm happy when my forecast is right, especially when the official prediction is wrong," he adds.

Wang gives an example: In late February a friend planned to visit Shanghai and asked the Dragon King if he should take winter clothes, noting that the weather was quite warm. But Wang forecast a strong cold front around March 5 and told his friend to plan on chilly weather. Indeed, there was sun and snow and the temperature dropped to around minus 3 degrees Celsius.

But the official weather bureau forecast the weather throughout March would not be too cold, saying the lowest would be around 3-4 degrees Celsius.

"The Arctic Oscillation has had a huge influence on China's weather since last October," Wang explains. "It led to the coldest winter since 1987 and the late spring this year. I estimate summer won't come until the beginning of June, compared with May 6 last year."

Right he was.

Wang draws on other fields, including physics, astronomy, geography and hydrology.

"Many factors need to be taken into account when making a forecast," he says. "You can't be a very good meteorologist if you only know meteorology. I might not get all the factors and forecasts right every time but I try to explore the truth of meteorology and get as close as possible."

Animated and articulate when discussing the weather and related issues, Wang is more withdrawn at other times.

"I used to be very shy before and could not even introduce myself naturally. Once I repeated my name, grade and major three times," he recalls.

Wang says he plans to stick with optics and engineering and doesn't plan to be a full-time weatherman. The weather is a hobby - "it makes me happy."

"When I feel pressured and busy, studying meteorology always helps me relax. Since I'm very interested in it, I can very quickly jump back into it," says the Dragon King.