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
44.7
52
27
38
26
69
February
40.4
32
28
26
53
41
March
38.3
38
42
49
37
37
April
51.0
46
56
55
21
May
38.0
36
31
50
48
June
45.0
35
28
40
53
July
33.6
33
46
29
21
August
45.6
37
32
51
31
September
69.4
76
63
72
64
October
74.1
74
57
76
70
November
66.5
70
49
68
71
December
47.5
49
67
34
67
Average
46.9
38.7
43.2
42.8
49.1
45.1
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
-14.6
-10
-14
-17
-16
-16
February
-14.4
-13
-16
-17
-20
-22
March
-11.9
-12
-10
-11
-12
-8
April
-6.2
-12
-5
-6
-6
May
0.2
-2
0
-1
2
June
7.2
5
6
6
8
July
10.5
12
10
8
9
August
9.6
10
8
9
10
September
7.2
6
8
6
6
October
1.9
1
1
-1
3
November
-4.7
-3
-3
-9
-1
December
-9.0
-12
-4
-12
-9
Average
-3.2
-12.3
-3.1
-2.1
-4.1
-2.2
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.