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
87.1
78
77
89
98
February
83.3
76
73
91
97
86
March
80.8
79
71
87
86
77
April
87.8
90
78
84
72
May
89.2
85
78
98
99
June
0
0
0
0
July
76.3
81
87
67
28
August
76.6
63
76
78
78
September
82.7
75
90
77
October
79.8
76
71
89
78
November
77.0
76
68
84
80
December
78.4
80
63
68
87
Average
81.9
77.7
76.8
79.9
84.9
76.6
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
-17.7
-13
-20
-13
-20
February
-14.1
-7
-15
-17
-20
-20
March
-8.1
-9
-7
-6
-11
-9
April
-1.5
-7
0
-1
0
May
9.7
10
9
11
13
June
18.8
17
19
19
19
July
18.6
20
19
18
9
August
15.8
17
15
15
19
September
10.6
9
11
9
October
0.7
0
-1
-1
1
November
-10.8
-6
-8
-17
-9
December
-13.1
-15
-11
-15
-13
Average
-1.9
-9.8
1.2
1.4
-2.6
-1.9
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.