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
79.2
78
76
80
75
82
February
84.3
70
83
76
85
96
March
84.1
91
86
81
88
76
April
83.8
81
86
77
90
May
89.0
92
89
90
91
June
93.3
98
95
84
97
July
85.0
69
86
94
87
August
88.3
83
89
89
91
September
88.5
78
87
93
96
October
88.1
91
82
94
86
November
89.8
87
90
96
92
December
81.9
78
67
88
88
Average
86.4
81.1
83.8
86.1
87.8
89.8
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
-21.7
-17
-23
-22
-14
-22
February
-24.6
-22
-30
-25
-16
-26
March
-17.8
-16
-14
-16
-19
-16
April
-8.3
-7
-8
-4
-8
May
-1.5
0
-2
0
0
June
7.1
7
11
6
6
July
11.6
10
12
12
14
August
10.7
10
10
10
14
September
5.4
5
7
5
5
October
-1.9
0
0
3
-1
November
-8.8
-4
-10
-6
-8
December
-11.4
-9
-7
-11
-8
Average
-6.1
-19.9
-5.5
-4.0
-3.2
-5.8
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.