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
80.6
76
79
81
87
95
February
78.4
78
78
80
78
72
March
76.5
74
69
70
72
84
April
87.9
95
90
78
81
May
84.4
79
82
96
94
June
86.5
81
74
98
83
July
87.1
89
89
93
80
August
84.6
80
85
90
78
September
89.4
94
87
91
88
October
86.2
81
84
92
89
November
81.1
71
77
67
77
December
78.2
69
82
73
97
Average
83.4
75.6
81.7
82.7
86.4
84.2
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.
Maximum temperatures (°C)
Month
Average
2024
2023
2022
2021
2020
January
-16.5
-14
-13
-19
-14
-20
February
-15.9
-11
-15
-17
-21
-21
March
-9.5
-9
-8
-9
-11
-8
April
-2.0
-9
-2
-4
-1
May
10.1
8
8
9
15
June
17.1
16
17
16
16
July
18.7
19
18
18
17
August
15.6
17
14
15
17
September
10.6
9
11
9
9
October
1.9
1
1
0
3
November
-8.0
-5
-6
-20
-6
December
-13.9
-16
-7
-12
-13
Average
-1.7
-12.6
0.4
1.8
-2.9
1.0
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.