"Space weather" describes the conditions in space that affect Earth. Since the conditions in space are entirely different from the conditions in the lower atmosphere which gives us winds, rain, storms etc., the word weather here is used figuratively.
The Sun sends out streams of fast moving high-energy particles, the so-called solar wind into the space. The Earth's upper atmosphere is usually shielded from the direct effects of the solar wind by the magnetic bubble of the magnetosphere. Therefore, most of the time space weather does not concern our everyday lives. However, the sun's condition is not steady, and when the space environment is disturbed by the exceptionally strong outputs of the Sun, it can cause power outages, telecommunications failures, satellite malfunction, higher doses of radiation during space and polar flights, etc.
The Hong Kong Observatory started the space weather webpage in 2004. This new webpage is an enhancement to inform the readers how space weather can affect our daily life and to provide the readers with the latest warnings of "storms" of space weather so that precautionary measures can be taken in a timely manner.