The runway is your one reference line. The wind is one arrow. All you ever do is relate that arrow to that line. Simpler than ground nav, where you juggle two streets.
000 N · 045 NE · 090 E · 135 SE · 180 S · 225 SW · 270 W · 315 NW
Snap any heading to the nearest anchor, then nudge. 110 = a hair clockwise of E, leaning SE.
Runway number x10 = heading. 29 -> 290, 11 -> 110, 04 -> 040, 36 -> 360.
The two ends differ by 18 (=180 deg). 29 - 18 = 11.
Picture the wind as an arrow flying AT you from its source:
| Wind source vs your nose | Result |
|---|---|
| within 90 deg of nose | HEADWIND |
| about 90 deg off (side) | CROSSWIND |
| more than 90 deg off | TAILWIND |
The fraction is just gap / 60 - treat the degrees like minutes on a clock face.
Then multiply by wind speed to get crosswind in knots.
| Gap | gap / 60 | Fraction |
|---|---|---|
| 15 deg | 15/60 | 0.25 = 1/4 |
| 30 deg | 30/60 | 0.50 = 1/2 |
| 40 deg | 40/60 | 0.67 (two thirds) |
| 45 deg | 45/60 | 0.75 = 3/4 |
| 60+ deg | 60/60 | 1.0 = all of it |
The gap is the "minutes," 60 is the "full hour," the fraction falls right out. Slightly over-estimates past 60 deg - which is the safe way to be wrong.
ATIS: wind 250 at 12.
1. West-ish wind -> use RWY 29 (290 deg). That hands you the headwind.
2. Gap = 290 - 250 = 40 deg. 40/60 = 0.67.
3. Crosswind = 12 x 0.67 = ~8 kt. The rest (12 x 0.77) is ~9 kt headwind.
4. 250 sits left of the 290 nose -> from the LEFT.
Call: left quartering headwind, about 8 cross.
Rotate the picture so the runway points up, then see which side the wind falls. Quick check: wind number lower than the runway heading -> usually LEFT; higher -> usually RIGHT.
BUT this flips across north. RWY 36 (360), wind 350: 350 looks "higher than 0," yet 350 is just left of north, so it is a LEFT crosswind. When numbers straddle 360, trust the picture, not the bigger/smaller shortcut. The TRAINER diagram always gets this right.