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
70.3
66
75
71
82
60
February
72.4
77
78
74
63
69
March
79.4
64
81
80
92
75
April
85.0
70
88
87
83
May
85.5
82
81
83
83
June
0
0
0
0
July
92.7
0
90
91
100
August
80.0
76
66
85
87
September
84.5
84
72
86
86
October
82.1
72
85
85
92
November
73.8
76
72
69
83
December
67.6
53
64
75
71
Average
80.4
68.4
76.9
77.7
84.4
81.4
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
-21.7
-21
-18
-23
-18
-25
February
-19.1
-15
-20
-22
-26
-24
March
-13.3
-14
-11
-14
-15
-15
April
-6.1
-11
-6
-7
-5
May
6.4
8
6
1
4
June
14.1
14
15
9
17
July
18.0
17
17
17
13
August
12.2
14
12
11
17
September
6.4
6
8
5
3
October
-4.0
-5
-5
-5
-5
November
-14.8
-10
-12
-18
-12
December
-18.6
-18
-14
-20
-19
Average
-5.4
-17.5
-4.1
-3.3
-5.3
-8.4
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.