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
75.1
73
81
72
79
77
February
78.7
76
82
81
76
69
March
80.1
71
85
77
88
84
April
82.1
74
86
87
77
May
74.6
83
65
67
68
June
81.4
84
71
88
64
July
82.7
66
72
93
78
August
82.4
88
87
85
83
September
85.3
89
92
70
79
October
79.7
87
72
76
89
November
70.3
73
61
71
84
December
77.4
80
85
86
70
Average
79.0
73.1
80.6
76.2
81.0
76.6
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
-19.0
-17
-17
-23
-16
-17
February
-21.2
-17
-23
-24
-20
-19
March
-13.3
-14
-17
-13
-10
-14
April
-5.4
-6
-3
-3
-7
May
4.1
12
4
2
2
June
13.2
18
12
12
10
July
19.3
16
18
22
18
August
18.1
20
20
18
18
September
12.2
17
15
12
9
October
2.8
5
5
6
0
November
-9.8
-6
-8
-4
-6
December
-16.7
-8
-17
-19
-14
Average
-3.3
-16.2
1.2
-1.6
0.0
-2.4
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.