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
83.3
78
81
85
80
92
February
86.3
78
87
87
88
86
March
83.3
72
81
86
82
91
April
83.6
87
78
77
73
May
87.6
83
87
84
85
June
90.5
92
90
92
88
July
85.4
79
79
87
84
August
89.6
87
89
97
79
September
89.3
81
96
88
89
October
87.9
82
82
86
90
November
85.3
90
79
78
84
December
81.5
70
74
87
91
Average
85.5
75.4
83.8
85.0
85.8
85.2
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
-13
-16
-21
-10
-17
February
-18.2
-15
-21
-21
-13
-18
March
-9.0
-6
-8
-10
-10
-11
April
-3.8
0
-2
1
-3
May
5.9
8
7
8
3
June
13.7
17
17
13
12
July
18.6
22
17
18
20
August
17.5
18
18
18
19
September
11.1
12
13
11
11
October
4.8
6
6
8
3
November
-5.5
-3
-5
-2
-5
December
-10.1
-8
-7
-10
-9
Average
-1.5
-12.8
2.3
1.4
2.7
0.3
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.