Weather is an interesting phenomenon of nature that influences our lives and yet, is something we have absolutely no control over. Most of the weather that occurs on our planet happens below 15,000 feet. That's great if you are flying a commercial jetliner at a high altitude of perhaps 30,000 feet where there is hardly any significant weather. For the majority of us we are "under the weather" most of the time. Weather is the utmost consideration of all pilots when planning a flight. Whether the pilot is flying a small airplane or flying a commercial jetliner, the weather at the departure airport, all along the route and at the destination airport must be constantly monitored. We will consider here the major weather conditions that affect pilots whether flying under conditions of VFR (visual flight rules) or IFR (instrument flight rules).