Summer rainfall over Europe is strongly influenced by the location of the jet stream. The jet stream is a channel of strong winds high up in the atmosphere, around ten kilometers about the Earth's surface. These winds blow generally from west to east but with large meanders, or wiggles, to the north and south. These strong winds steer our weather systems and the rain that they bring. In this animation, the colored arrows show these upper level winds. The orange and red arrows show the regions of strongest winds, which make up the jet stream. The jet stream is very mobile and moves around from day to day. Sometimes it is found to the north of the UK and other times it is found to the south. This wandering of the jet stream has a big influence on our weather.