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
2023
2022
2021
2020
January
60.6
39
68
61
72
February
53.0
32
42
60
53
March
58.8
48
49
33
55
April
77.4
91
58
May
83.1
75
96
90
June
76.8
90
75
51
July
59.2
100
73
63
0
August
67.8
57
71
66
September
78.2
69
86
88
October
77.0
67
82
81
November
71.7
59
87
75
December
64.0
57
57
57
Average
66.4
39.8
67.7
72.2
60.5
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
2023
2022
2021
2020
January
-10.0
-9
-13
-9
-15
February
-8.2
-9
-9
-10
-12
March
-4.0
-4
-4
-7
-5
April
1.6
2
1
May
9.6
9
14
12
June
14.7
16
13
15
July
14.8
12
14
13
14
August
14.0
12
13
16
September
10.7
10
10
10
October
4.8
3
3
6
November
-3.7
-3
-8
0
December
-6.2
-4
-5
-7
Average
2.0
-8.9
2.6
2.6
2.8
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.