Wind Meter anemometer 1.0.5
the author of this app says:
Wind Meter is sound based anemometer to estimate wind speed.
It works by analyzing the sound of wind passing the device microphone.
Wind Meter includes compass integration, so you can easily find wind direction too.
Wind Meter supports multiple units of measure including MPH, Knots, Km/h, m/s and dynamic Beaufort scale.
There is an ability to calibrate your phone model to obtain more accurate results.
This application is not meant to be used in place of scientific instrumentation, but it can come close to real anemometer device.