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
85.8
73
85
81
94
91
February
83.2
79
84
81
99
82
March
80.9
80
73
87
85
87
April
90.3
95
95
89
79
May
90.5
89
77
98
100
June
90.5
63
100
100
0
July
86.3
84
85
90
84
August
83.4
78
82
81
84
September
86.9
88
88
88
83
October
86.8
84
82
88
82
November
84.4
85
77
89
83
December
82.9
81
75
74
89
Average
85.1
78.3
83.9
83.6
89.1
85.8
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
-17.8
-17
-12
-19
-13
-21
February
-14.1
-9
-16
-17
-19
-20
March
-7.0
-8
-8
-5
-11
-9
April
-2.8
-9
0
-1
-1
May
10.7
9
9
12
13
June
17.7
16
18
17
18
July
18.4
19
18
17
18
August
15.4
17
14
14
18
September
10.0
9
11
8
9
October
0.8
0
-1
0
1
November
-9.1
-6
-8
-17
-8
December
-13.2
-15
-12
-15
-13
Average
-1.6
-12.5
0.5
1.1
-1.4
0.5
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.