What's appen with my analog pin

[gcjr]

@pierrot10

When I move the van to 180°, then to the south, the read, at A0, 787 whch is West.

if the anemometer it powered by 5V, South is half, 2.5V.

2.5V read by a 3.3V ADC is 75% of 1024 or 775

you could try translating the voltage using a pot so that your ADC sees 3.3V when the anemometer is outputting 5V