7Timer! is a series of web-based meteorological forecast products, mainly derived from the NOAA/NCEP-based numeric weather model, the Global Forecast System (GFS). 7Timer! was firstly established in July 2005 as an exploration product under supported of the National Astronomical Observatories of China and had been largely renovated in 2008 and 2011. Currently it is supported by the Shanghai Astronomical Observatory of Chinese Academy of Sciences. It was firstly designed as a weather forecast tool for astronomical purpose, as the author himself is a long-term star gazer and was always annoyed by fluky weather conditions.


The point that 7Timer! significantly differ from many other weather websites is that it covers the entire globe (not just the main cities) with high spatial resolution (~20km). In another word, it is delivering forecast for over 1.5 million locations four times a day! In addition, it offers four products that aim at providing specialized forecasts for users in different concentrations (such as meteorologists, astronomers, and civil users). The full-set data are also freely available in forms of human or machine-readable APIs for the use of website owners or programmers.

Term of Use and Disclaimer

The weather data distributed in this site are entirely free – you have to right to use, redistribute or reproduce them without notifying me, as long as you are not using them for commercial purpose. Just be aware that weather forecasting is as challenging as in the stock market – so use these data at your own risk.


7Timer! was supported by Dr. Cui Chenzhou on behalf of the National Astronomical Observatories of China in 2005-2010, and is then supported from Dr. Lin Qing and Mr. Tang Haiming of the Chinese Network for Astronomy Popularization, Shanghai Astronomical Observatory, Chinese Academy of Sciences. Big thanks also go to Attilla Danko who inspired me to establish 7Timer!; to Li Zuqiang and Dr. Johnson Lau who had been extensively involved in the development of data reduction scripts; to Shi Liaoshan who help testing every new releases; to littlePig and Max who had given help on starting code works of Google Maps API; as well as to numerous people who have contributed helpful suggestions and encouragements.

Scientific Usage

There is one publication talking about the accuracy of 7Timer! data:

Ye, Q.-Z. 2011, Forecasting Cloud Cover and Atmospheric Seeing for Astronomical Observing: Application and Evaluation of the Global Forecast System, Publications of the Astronomical Society of the Pacific, 123, 113-124

Please refer to this paper if you would like to learn more about 7Timer! scientifically. If you are writing a paper that utilize data from 7Timer!, a citation of this paper will be great.

About the Author

The author is currently a graduate student in astronomy. He is a long-time hobbyist of astronomy and meteorology. He also holds a Bachelor of Science degree in atmospheric sciences.

7Timer! is proudly supported by Chinese Network for Astronomy Popularization at Shanghai Astronomical Observatory, Chinese Academy of Sciences.