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
85.5
77
76
77
88
91
February
81.4
74
78
75
85
94
March
87.7
91
91
78
90
91
April
84.4
73
75
89
95
May
80.2
79
89
86
78
June
0
0
0
0
July
88.9
72
92
96
75
August
88.2
87
91
92
89
September
83.8
77
86
79
93
October
81.4
76
84
75
81
November
88.5
76
80
93
93
December
81.1
84
58
94
81
Average
84.7
82.8
79.3
83.1
86.9
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
-23.8
-23
-22
-25
-22
-23
February
-24.5
-20
-28
-26
-26
-26
March
-20.5
-19
-23
-20
-23
-20
April
-13.9
-8
-11
-13
-11
May
1.0
6
5
1
-2
June
10.4
14
9
11
11
July
17.2
21
20
17
16
August
14.8
16
17
14
15
September
7.3
9
8
8
7
October
-2.7
2
-2
2
-3
November
-13.4
-10
-11
-12
-15
December
-20.0
-14
-23
-25
-20
Average
-7.1
-21.2
-3.0
-5.6
-6.5
-6.3
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.