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
78.5
87
71
70
86
81
February
82.3
81
83
83
85
82
March
86.6
79
84
83
90
93
April
91.0
94
89
89
92
May
94.7
98
97
95
95
June
91.0
84
94
94
92
July
90.7
84
94
92
87
August
91.3
92
84
89
96
September
91.6
90
91
93
96
October
91.8
95
83
94
95
November
89.5
93
90
85
88
December
83.1
74
84
89
89
Average
88.3
81.9
87.2
87.4
90.4
90.8
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.