Wind noise is always a potential hazard when you're recording outdoors, particularly if your microphone isn't equipped with a wind shield. Fortunately, the noise filter in Audacity, the free open-source audio application, can help you reduce or eliminate the wind noise from a sound file. It won't make your file sound like it was recorded in a sound booth, but it can help voices and other important sounds stand out from the roar of the wind.
Load the sound file into Audacity. Click the "Play" button on the top tool bar to listen to the file. Find a section of the recording that contains nothing but wind noise and is at least two seconds long. Click the "Stop" button when you've found a segment that's long enough. Note the time at which this area appears on the waveform in the editing window.
Click on one side of the section containing wind noise and drag the cursor over to the other side of the segment to select it. Preview the sample by clicking the "Play" button; make sure that the sample does not contain any voices or other sounds you want to save.
Click the "Effects" menu and select "Noise Removal." Click the "Get Noise Profile" button, which is located in the top half of the "Remove Noise" dialogue box.
Open the "Edit" menu, then click "Select" and "All." Click "Effects" and select "Noise Removal" once more. Move the "Less/More" slider to the centre, then click the "Preview" button to listen to the result. Move the slider back and forth, listening to the preview. Find the position at which Audacity reduces the wind noise as much as possible without seriously distorting the voice or causing other strange-sounding artefacts to occur. Click the "Remove Noise" button.
The longer the sample of noise you select when you gather the noise profile, the better. For the best results, move the "More/Less" slider as close to the "Less" side as possible.
If you set the "More/Less" slider too close to "More," Audacity removes all the sound from the file. If the setting is too close to "Less," strange beeping and warbling sounds may appear as Audacity lets some of the frequencies of the wind noise through the filter.