26 September 2023

False: US Embassy in Beijing does not make unauthorized weather forecast

Chinese social media posts accused U.S. diplomats of disseminating unauthorized weather data illicitly, but the forecast comes from a non-profit atmospheric data project that has nothing to do with the U.S. government.


Various posts on Twitter, Reddit and Weibo in June and July claimed that the U.S. Embassy in China disseminated unauthorized temperature forecasts for Beijing, accusing it of violating the country’s meteorological regulations.

In China, violations of the Meteorological Administration’s regulation on “weather forecast release and dissemination” could result in a fine of 50,000 yuan and other penalties.

Those users also said some of the forecasts from the periods of June 21 to 27 and June 30 to July 6 were 5 to 7 degrees Celsius higher than the official data.

The same claims were reposted on Netease and overseas Chinese sites such as Huaglad and Bannedbook.

They are all misleading, however.

Annie Lab found that the U.S. Embassy in China only provides real-time air quality data, not weather forecasts.

A keyword search led us to a website that is confusingly titled, “Beijing-US Embassy Air Pollution: Real-time Air Quality Index,” which is actually not run by the U.S. Embassy.

We believe the images used in the claims are screenshots of this website, as the design and color scheme are identical.

Graphics used in the Chinese social media posts (left) and content retrieved from the Beijing-US Embassy Air Pollution: Real-time Air Quality Index website in English (right).

We learned the site is maintained by the World Air Quality Index project, a Beijing-based non-profit initiative developed by professionals in the fields of environmental science, data science, system engineering, and visual design.

The project pulls data from different sources. It explicitly credits the U.S. Embassy in China and the Beijing Environmental Protection Monitoring Center for the data on PM2.5.

The weather data is credited to the Open Weather Map and the Citizen Weather Observer Program.

Rachael Chen, a spokesperson for the U.S. Embassy in Beijing, told Annie Lab in a written reply that the data for air pollution is part of its Air Now Quality Monitor, an initiative that began in 2008.

A 2022 research from Carnegie Mellon University and the University of Queensland says the U.S. Embassy has since been tweeting hourly air-quality readings.

None of the U.S. official air quality monitoring efforts released on Twitter and its website contain any weather forecast data.

Significant differences

Annie Lab also looked into the temperature discrepancies between China’s official forecast by the Chinese Meteorological Agency and the data sources used by the non-profit website.

We cross-checked the data, and there is indeed a 5-7 degrees Celsius difference in their maximum temperature.

Comparison of weather forecast from CMA’s video library (bottom) and from the Open Weather Map and Citizen Weather Observer Program (top).

The differences in the weather forecast should be a cause for alarm, said Lam Chiu Ying, the former head of the Hong Kong Observatory.

Lam said a disparity of 5 to 7 degrees Celsius in weather forecasts means “one of the two predictions is significantly wrong,” and it could be caused by incorrect initial data.

Even different computer models “shouldn’t produce results that are so much different,” Lam also said.

Meanwhile, David Lam, a scientific officer at the Hong Kong Observatory, said a “chaotic atmosphere” could make forecasting weather a challenge to the meteorological community.

Factors such as statistical methods or AI and machine learning could contribute to potential discrepancies when it comes to forecast data, he added.