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
83.2
86
65
72
89
99
February
69.3
74
62
55
71
77
March
81.2
80
75
93
72
82
April
88.7
86
93
89
74
May
93.7
93
87
99
99
June
90.5
85
83
94
96
July
83.7
80
81
83
93
August
76.5
74
69
73
90
September
81.4
77
73
89
90
October
77.5
81
65
76
92
November
68.4
70
55
83
67
December
75.7
84
73
64
81
Average
82.0
79.7
79.0
76.0
83.2
87.6
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
-14.0
-15
-13
-14
-12
-21
February
-11.9
-8
-11
-11
-13
-13
March
-5.5
-5
-5
-3
-8
-6
April
3.8
-2
4
3
4
May
13.1
12
13
14
15
June
17.9
16
21
17
18
July
19.3
19
18
18
18
August
15.8
17
15
14
18
September
10.2
9
10
9
10
October
1.9
0
1
0
3
November
-8.1
-5
-7
-15
-8
December
-11.7
-15
-10
-9
-11
Average
1.4
-10.7
1.7
3.2
1.7
3.0
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.