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
82.7
72
74
84
94
85
February
77.1
82
65
83
86
83
March
81.2
80
82
87
78
72
April
93.8
95
98
90
83
May
95.4
99
83
97
100
June
98.4
89
100
97
100
July
92.2
87
86
92
94
August
85.8
60
90
82
99
September
89.6
89
93
86
93
October
79.2
73
82
76
82
November
79.6
71
76
87
88
December
78.9
77
90
70
81
Average
86.5
78.6
80.9
87.3
86.9
90.2
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
-15.2
-15
-13
-16
-13
-20
February
-14.7
-10
-14
-16
-18
-19
March
-8.1
-8
-8
-7
-11
-9
April
-1.8
-5
1
-1
-1
May
11.8
12
11
11
13
June
18.3
16
19
18
18
July
19.6
20
18
18
17
August
15.0
16
15
14
18
September
8.8
7
9
8
9
October
-1.5
-1
-2
-1
-1
November
-10.7
-6
-10
-14
-10
December
-13.0
-15
-16
-15
-12
Average
-1.8
-11.0
0.6
1.7
0.2
0.3
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.