The ability to block wind is inherent in the fabric. Proper washing will not affect its ability to block wind.
Turn item inside-out and machine wash warm with liquid detergent specifically for membrane clothing (available in specialist sports shops). Tumble dry cool, or hang drying is the safest.
Remember to zip all pockets and close all Velcro cuffs before washing to prevent any damage caused by the machine.
Do not dry clean, use bleach or fabric softeners.
It is better to care for the garment often with a little detergent than rarely with a lot of detergent.