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
64.9
63
61
67
83
59
February
81.7
79
88
77
88
88
March
83.6
95
78
93
96
82
April
89.4
86
79
93
92
May
91.7
95
94
90
92
June
95.7
93
100
98
98
July
97.6
98
100
97
98
August
91.8
91
96
92
93
September
91.3
88
93
95
97
October
88.3
91
98
83
100
November
84.2
94
82
85
December
74.7
64
47
78
Average
86.5
80.2
88.1
83.1
91.1
90.0
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
-8.1
-7
-8
-9
-5
-7
February
-7.7
2
-6
-7
-10
-5
March
0.9
4
-5
0
9
2
April
8.0
4
3
13
8
May
19.8
24
16
20
18
June
26.4
28
24
30
27
July
27.3
27
26
30
28
August
25.8
27
25
29
27
September
21.7
24
23
25
21
October
12.2
13
16
15
10
November
1.9
6
1
5
December
-6.8
-1
-8
-6
Average
9.7
-1.8
11.9
9.6
14.5
13.1
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.