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
75.1
70
58
80
88
64
February
86.1
78
89
92
90
86
March
91.9
93
91
85
96
92
April
92.8
88
98
90
92
May
97.3
97
100
97
96
June
93.7
91
100
92
98
July
95.0
78
97
99
96
August
90.4
71
94
97
93
September
86.3
56
93
82
93
October
79.3
72
76
73
88
November
73.0
66
68
69
83
December
74.6
57
82
86
77
Average
87.7
81.6
77.8
90.9
89.5
90.1
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
-20.1
-23
-15
-24
-17
-22
February
-20.7
-15
-21
-23
-23
-18
March
-10.0
-9
-12
-11
-11
-13
April
-1.9
4
0
-3
-3
May
12.0
19
11
9
8
June
19.3
21
22
20
18
July
22.1
25
22
22
21
August
19.6
22
21
19
19
September
12.6
15
15
12
12
October
2.9
5
5
5
1
November
-10.9
-6
-8
-7
-11
December
-18.1
-10
-21
-24
-18
Average
-1.1
-16.2
4.0
1.5
0.3
-1.6
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.