How can I read wind direction on a weather diagram?

“Wind direction” names where the wind comes from, not where it is going. So a north wind comes from the north and blows generally southward. First identify the symbol: it might be an arrow or a wind barb, and they should not automatically be read the same way. Look for a legend, caption, or symbol key explaining what the mark represents. If there is no key, avoid assuming that an arrow’s point gives the wind’s source.

For the station weather plots described by the National Weather Service, the long shaft indicates direction and points toward where the wind is coming from. The short feathers and pennants encode wind speed, not direction. [S1]

Labeled symbol guide

1. Long shaft: follow it toward the source direction; compare it with the compass directions on the plot.
2. Short feathers and pennants: these represent speed, not the direction the wind comes from. [S1]
3. Compass reference: use the diagram’s north marker or compass labels to name the shaft’s direction.

This convention is established for those station plots. The source does not establish that every weather diagram, or every arrow symbol, uses the same convention. [S1]

Here are simple reading examples. Assume the diagram has a clear compass and, where noted, a legend.

1. Barb shaft points north: On a station plot using the convention above, read it as wind coming from the north. The wind is generally moving southward. The shaft gives direction; its feathers or pennants give speed. [S1]
2. Barb shaft points southeast: Read it as wind coming from the southeast. The shaft’s direction—not the position of its feathers—is what you use to name the source direction. [S1]
3. Arrow with a legend saying “arrow points toward where wind blows”: If its tip points east, read the wind as blowing eastward, so it comes from the west. That reading follows the legend’s stated arrow convention; it is not a rule for all diagrams.
4. Arrow with no legend: Mark it as unclear rather than guessing. Check the diagram’s caption or ask whoever provided it what the arrowhead represents.

Use this short sequence: find the compass reference, identify whether the mark is a barb or an arrow, then check the legend before interpreting its direction. For a station-plot wind barb covered by the cited convention, follow the shaft toward the direction the wind comes from; treat the feathers and pennants as speed markings. [S1] For arrows, use the legend’s explanation. If the symbol key is missing or ambiguous, write down what is unclear instead of presenting a guess as certain.

Copyable note: “Symbol: [barb/arrow]. Compass reference: [north marker or labels]. Legend says: [what the symbol indicates]. Direction read: wind comes from [direction] / arrow points toward [direction]. Unclear detail: [what needs confirmation].”