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
75.7
59
79
69
76
84
February
71.7
65
68
67
78
72
March
81.8
72
78
78
83
85
April
88.9
90
82
94
84
May
90.5
96
86
90
86
June
91.3
74
96
98
89
July
83.6
49
82
96
91
August
93.2
93
93
90
94
September
91.6
86
89
91
92
October
86.8
74
84
89
91
November
74.8
72
79
79
67
December
70.1
61
72
67
72
Average
83.7
66.5
77.0
82.4
87.8
85.5
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
-15.2
-11
-14
-20
-10
-14
February
-14.6
-8
-15
-16
-11
-12
March
-6.4
-4
-5
-8
-4
-7
April
1.8
4
2
6
1
May
10.6
13
12
11
8
June
18.2
22
20
18
17
July
20.0
15
19
21
23
August
18.8
19
20
20
19
September
13.7
18
15
15
11
October
6.7
9
10
11
3
November
-4.7
-3
-2
-1
-2
December
-10.0
-6
-8
-11
-9
Average
2.2
-8.8
4.8
4.2
5.6
3.1
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.