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
88.3
78
84
91
97
90
February
79.4
85
67
85
83
March
81.1
89
0
89
87
87
April
82.3
0
95
97
95
May
95.3
88
97
98
100
June
84.0
94
66
98
91
July
88.7
99
55
99
95
August
87.5
92
85
82
88
September
88.1
82
84
90
92
October
80.8
85
62
74
88
November
77.1
76
79
50
83
December
82.1
78
71
79
90
Average
85.6
84.2
74.9
77.8
90.9
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
-17.8
-18
-15
-15
-12
-21
February
-11.2
-11
-12
-16
-14
March
-4.3
-7
-4
-3
-3
-6
April
4.0
0
4
4
4
May
14.0
14
14
15
16
June
19.9
19
23
21
18
July
21.6
23
21
19
20
August
17.7
20
18
15
20
September
11.9
10
12
11
12
October
2.0
0
1
1
3
November
-9.9
-6
-9
-14
-11
December
-14.5
-18
-11
-12
-14
Average
1.5
-13.8
4.4
4.1
4.6
0.5
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.