IFR: Vis < 3SM, BKN/OVC < 010
MVFR: Vis <= 5SM, BKN/OVC <= 030
QVFR: Vis <= 6SM, SCT < 020, Wind >= 20KT, Temp-Dew spread <= 3
Copyright © 2014 Steve Kollmansberger
Data from NOAA AWC Data Server