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
79.2
82
69
78
89
83
February
78.4
77
64
86
87
82
March
88.1
93
87
85
85
87
April
91.3
84
88
98
97
May
90.2
83
91
90
92
June
75.0
100
23
0
0
July
89.8
67
89
93
94
August
89.4
81
92
90
94
September
83.8
78
79
90
88
October
73.5
72
70
61
90
November
75.1
71
75
69
79
December
80.6
68
75
83
93
Average
85.5
84.5
76.5
83.5
86.4
90.1
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
-17.6
-26
-10
-1
-18
-24
February
-18.3
-18
-18
-1
-28
-24
March
-13.8
-15
-14
-2
-18
-15
April
-5.6
-4
-1
-5
-5
May
8.3
12
9
6
5
June
16.8
19
16
18
17
July
20.9
26
22
21
17
August
16.7
18
19
17
17
September
9.4
12
10
10
9
October
-1.3
1
-1
1
-2
November
-12.3
-9
-10
-12
-13
December
-16.7
-14
-3
-12
-18
Average
-3.4
-20.3
1.8
5.0
-2.4
-3.0
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.