Many people check the weather because they want to know if meteorologists have predicted precipitation in the forecast. An unexpected downpour can ruin the best laid plans. A weather map that shows two black dots indicates that rain is expected or currently in the area. You may also notice a bar at the top of the map that shows a lighter color, such as lime green for rain or sky blue for snow, and a darker color to indicate whether precipitation in the area is light or heavy. Four dots in a cross formation indicate heavy rain. Two snowflakes indicate snow while four snowflakes in the shape of a cross indicate heavy snow.
A combination of symbols and colors can quickly alert you to any potential severe weather such as ice storms or tornado activity. A symbol in the shape of an "R" with an arrow pointing down diagonally indicate the presence of thunderstorms. If a solid red area is close to your geographic location, go to a safe spot such as a shelter or basement because a tornado warning is active. A yellow area indicates a severe thunderstorm warning. An aqua blue area depicts a flood warning and a light green area is a flash flood warning so stay off of dangerous roadways. A white area depicts a winter weather advisory so be sure that you are prepared for snow and sleet.
It is helpful to know if fronts are approaching because fronts can cause a sudden change in the weather or temperature. A blue arc with two circles on top of it indicate a cold front, while a red arc with two circles on top indicate a warm front.
If your area is particularly prone to fog, it can save you time to know the symbols ahead of time that depict fog conditions. Two lines that look like an equal sign are symbols of fog while three parallel lines depict dense fog. A gray color over an area on the weather map also indicates fog.
If you are planning an outdoor activity such as sailing, it may be helpful to learn the symbols that depict wind speeds. A long, straight line indicates that wind speeds are only one to two miles per hour. A long, straight line with one large, thin diagonal line extending toward the left and one small, thin diagonal line extending toward the left indicate wind speeds are at 15 to 20 miles per hour. A straight line with four large, thin diagonal lines indicate wind speeds are at 44 to 49 miles per hour.