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
73.0
79
59
74
81
63
February
86.6
84
84
92
85
80
March
90.5
88
90
85
92
89
April
91.9
89
90
90
88
May
89.8
77
83
91
93
June
91.4
76
100
94
90
July
83.4
48
92
87
87
August
87.6
55
91
95
81
September
84.8
46
90
75
87
October
79.0
72
83
90
65
November
69.7
60
70
59
75
December
72.8
72
68
84
79
Average
84.6
83.9
70.7
86.7
86.5
82.8
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
-16.2
-19
-12
-18
-13
-17
February
-15.6
-9
-17
-19
-18
-9
March
-5.2
-5
-7
-6
-5
-7
April
4.5
8
3
3
1
May
15.9
24
13
13
12
June
22.3
23
23
24
21
July
24.2
26
25
25
24
August
22.2
23
25
22
20
September
15.2
19
20
16
14
October
5.4
8
9
7
1
November
-8.8
-4
-7
-5
-9
December
-14.2
-6
-16
-20
-11
Average
2.5
-12.9
5.8
5.1
4.2
3.4
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.