Crosswind chart guide: reading the wind triangle on final

If you trained from the FAA Airplane Flying Handbook or the Pilot's Handbook of Aeronautical Knowledge, you've seen the crosswind chart: a quarter-circle pattern of curved arcs (wind speed) crossing straight radial lines (angle off the runway). Drop a finger on the right arc, slide it to the right radial, and read the crosswind on the bottom axis and the headwind on the side. No arithmetic, no fingers-in-the-cockpit calculator.

What the chart shows

The two axes are the building blocks of every wind triangle:

• X-axis (horizontal): crosswind component, in knots.
• Y-axis (vertical): headwind component, in knots. If the wind blows toward you down the runway it is positive; if it blows from behind you it becomes a tailwind.
• Curved arcs: total wind speed. Each arc is a constant wind speed (10 kt, 15 kt, 20 kt, etc.).
• Straight radial lines: the angle between the wind and the runway, measured from 0° (right down the runway) up to 90° (directly across).

To read the chart you only need three numbers: the runway heading, the wind direction, and the wind speed. The METAR gives you the second and third; the airport diagram gives you the first.

Step-by-step

1. Find the angle between the wind and the runway. Subtract the runway heading from the wind direction. Runway 24 heads 240°; wind from 270° is 270 − 240 = 30°.
2. Find the right radial. Walk the chart radials until you hit the angle you computed (here, 30°).
3. Find the right arc. Slide along that radial until you cross the arc that matches the reported wind speed (say, 12 kt).
4. Drop perpendiculars. Read straight down to the x-axis for the crosswind component, and straight across to the y-axis for the headwind.

For 30° / 12 kt, the chart confirms 6 kt crosswind and roughly 10 kt headwind — which matches the sine rule (12 × sin 30° = 6; 12 × cos 30° ≈ 10).

Reading the chart in your head

You can shortcut the chart entirely once a few anchor points are second nature:

• 0° off: all headwind, no crosswind.
• 30° off: crosswind ≈ half the wind, headwind ≈ 0.87 × wind. The chart radials are roughly evenly spaced through 30°.
• 45° off: crosswind ≈ 0.7 × wind, headwind ≈ 0.7 × wind. The "everything cuts in half along the diagonal" mental model.
• 60° off: crosswind ≈ 0.87 × wind, headwind ≈ half the wind. A symmetric flip of the 30° case.
• 90° off: all crosswind, no headwind. The arc meets the x-axis at the full wind speed.

When the chart gets you in trouble

• Gust component. The arcs are drawn at fixed wind speeds. Use the gust value (not the steady wind) when deciding limits — re-read the chart at the gust speed and compare the worst-case crosswind to the POH/AFM demonstrated value.
• Variable winds. A METAR like VRB05G15KT means the wind is bouncing across a range; pick the worst-case bearing for your runway and the gust speed.
• True vs magnetic. METAR body text is true; ATIS and tower are magnetic. If the chart looks "off" by a few degrees it's often a frame-of-reference mismatch.
• Wind shifts on short final. Tower reports the surface wind at the airport's anemometer, but the wind at your altitude on short final can differ. Cross-check with the windsock when you have one in view.

From chart to decision

The crosswind chart only tells you what the wind is doing. It does not tell you whether you should fly. The decision combines:

• The crosswind read off the chart at the gust value.
• The aircraft's POH/AFM demonstrated crosswind component (and any operating limitations).
• Your personal minimum, which usually sits below the demonstrated value.
• The runway's length, surface, and condition.
• Conditions you can't read off the chart: fatigue, terrain, available alternates, and recent currency.

Skip the chart with one tool

If you don't have the chart printed and you don't want to do the math, the runway crosswind calculator reads METARs and TAFs for nearby airports and lists the runways with their crosswind components already computed. It also lets you filter by runway length and surface, and pick a future departure time to plan ahead.

Related guides and tools

• Crosswind component calculator guide — the math and the rules of thumb.
• VFR flight planning checklist — where the wind check sits in the full preflight flow.
• Runway crosswind calculator — find a runway with the wind you want.
• Glide-aware VFR flight planner — wind-aware route planning that respects glide range.