Small Aircraft
Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Air Traffic Control Military 13; Flight Crew Last 90 Days 14; Flight Crew Total 5490; Flight Crew Type 1050
Confusion; Time Pressure; Troubleshooting
Deviation - Track / Heading All Types; Ground Event / Encounter Other / Unknown; Inflight Event / Encounter Weather / Turbulence
Flight Crew Became Reoriented
Airport; Incorrect / Not Installed / Unavailable Part
IFR flight plan from ZZZ TO MVN.  MVN voice ASOS reported winds as variable at 3 knots.  Foreflight reported 'observation not available for MVN.'  Turning base to final for Runway 5; I knew I had a tailwind and I double checked the gear which when up feels like a tailwind.  As I was turning base to final the FBO transmitted the ASOS was incorrect; the winds were 280 at 15 gusting to 18.  I made a low approach entered a left base and landed Runway 23.  The landing was uneventful.  I thanked the FBO for the heads up call.  The FBO said this was a problem when the wind was out of the north and northwest and it had been reported to FAA.
General aviation pilot reported an unexpected tailwind during final approach to MVN airport and was told the ASOS has been reporting incorrect wind information.