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
79.4
82
61
83
75
83
February
70.3
66
76
47
73
73
March
75.8
82
70
91
77
75
April
83.4
86
90
68
70
May
88.3
89
70
91
100
June
84.8
80
95
94
88
July
85.7
100
92
81
86
August
81.6
63
85
76
91
September
91.1
85
93
96
100
October
92.6
86
93
99
99
November
84.7
79
83
92
91
December
80.0
71
82
78
93
Average
83.2
76.4
78.0
84.9
84.1
86.8
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
-13.7
-10
-10
-15
-11
-17
February
-11.6
-8
-12
-18
-16
-16
March
-6.2
-8
-6
-8
-8
-7
April
-2.5
-7
0
-3
0
May
9.4
7
7
10
12
June
15.7
14
18
14
15
July
16.7
19
17
15
15
August
12.5
15
13
14
16
September
9.9
9
11
9
13
October
2.6
2
3
1
3
November
-6.8
-3
-4
-15
-3
December
-9.0
-13
-5
-11
-9
Average
1.4
-9.2
-1.7
1.8
0.1
1.7
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.