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
73.6
61
63
82
68
February
84.3
69
73
89
89
92
March
88.0
88
84
84
93
82
April
88.8
85
83
90
88
May
86.1
88
74
86
82
June
86.0
90
82
86
80
July
91.1
90
89
88
89
August
87.4
80
87
83
87
September
85.8
74
91
86
87
October
77.4
77
80
73
75
November
71.8
68
62
71
74
December
74.7
66
76
85
66
Average
83.6
73.3
79.3
81.6
84.8
82.6
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
-17.2
-16
-13
-21
-15
February
-16.8
-11
-17
-18
-16
-12
March
-6.3
-7
-10
-5
-2
-8
April
3.0
5
3
4
0
May
13.1
20
10
10
11
June
20.0
24
19
21
18
July
23.3
23
24
25
24
August
20.7
22
22
21
20
September
14.3
19
18
15
12
October
4.1
6
7
8
1
November
-9.8
-5
-8
-4
-9
December
-15.8
-6
-19
-21
-4
Average
1.6
-12.5
5.7
3.6
6.0
3.5
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.