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
75.4
82
71
82
61
72
February
81.9
68
81
80
79
92
March
84.3
79
80
82
94
89
April
80.9
65
79
80
82
May
81.5
71
87
83
75
June
82.5
81
79
87
82
July
77.8
71
62
91
83
August
87.0
87
83
90
84
September
87.9
86
92
82
88
October
79.9
62
87
66
94
November
77.6
81
72
78
76
December
75.0
74
64
87
74
Average
81.5
76.1
75.2
79.3
82.3
82.7
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
-17.8
-13
-15
-21
-12
-15
February
-16.0
-13
-18
-17
-15
-15
March
-9.6
-9
-11
-9
-7
-9
April
-1.2
-2
0
2
-2
May
9.1
12
10
10
6
June
17.1
23
18
17
16
July
21.5
21
20
22
23
August
19.5
21
21
20
19
September
14.2
19
16
14
13
October
5.8
6
8
10
2
November
-5.0
-4
-3
-2
-5
December
-13.2
-5
-14
-16
-12
Average
0.5
-12.3
4.0
3.1
3.6
1.9
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.