Weather Basics - Effects of Wind Conditions in Sailing

• True and Apparent
  The Wind that you feel when the Sailboat is not moving is called True Wind, while Apparent Wind is the one you feel when the vessel is moving. This is the combination of the True Wind and the one created by the Sailboat moving through the air.
  
  Here are some things worth-knowing about True Wind and Apparent Wind:
  
  • Except on a dead run, Apparent Wind is always forward or ahead of the True Wind.
  • The speed of Apparent Wind decreases when the True Wind moves further behind.
  • Any small change in the direction of the True Wind will result to a big difference in the direction of the Apparent Wind.
  
  
• Offshore and Onshore Winds
  Offshore Winds refer to Winds blowing from the land and out towards the water. They move water away from the shore, which results to lower Tides. When you go sailing in an Offshore Wind, you may have a wrong expectation when you see peaceful waters near the coast. This may mean stronger Winds and great waves out in the sea.
  
  Unlike Offshore Winds, Onshore Winds blow from the waters and out towards the land, which leads to Tides higher than anticipated.



• Estimating Winds through ocular observation
  There are various signs that can help you in estimating the Wind, especially its direction. Flags, as simple as they are, can greatly inform you about Wind direction in your area. A Wind fly, usually located at the top of the Mast, will give you an idea on where the Wind is coming from, as well as smoke from chimneys and vents.