Percentage of observations where the VFR minimums for ceiling and visibility are met: visibility of 5 mi or more and a ceiling of 3,000 ft or more. Only observations between sunrise and sunset are taken into account.
Marginal VFR conditions (%)
Month
Average
2024
2023
2022
2021
2020
January
98.7
98
99
98
100
100
February
99.4
99
99
99
99
100
March
99.6
99
100
100
100
99
April
97.7
99
98
100
99
May
99.7
100
99
99
100
June
99.8
100
100
100
100
July
99.3
100
99
100
98
August
99.6
100
100
100
98
September
99.2
100
100
99
97
October
99.2
100
100
98
98
November
99.8
100
100
100
100
December
99.2
99
100
99
100
Average
99.2
98.7
99.6
99.3
99.4
98.9
Marginal VFR conditions or better during daylight period
Percentage of observations where the MVFR minimums for ceiling and visibility are met: visibility of 3⅛ mi or more and a ceiling of 1,000 ft or more. Only observations between sunrise and sunset are taken into account.