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
73.9
79
46
73
58
91
February
71.1
62
62
81
75
66
March
83.3
80
74
84
78
89
April
90.6
96
91
86
76
May
88.5
92
91
52
99
June
95.5
95
97
88
96
July
92.7
90
81
94
96
August
89.8
80
93
94
September
86.7
100
83
87
92
October
76.3
81
79
51
84
November
70.7
61
63
87
43
December
62.3
60
61
77
29
Average
83.6
73.3
80.8
83.8
79.3
84.7
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
-15.1
-17
-9
-15
-6
-23
February
-12.9
-10
-12
-11
-17
-17
March
-5.1
-6
-6
-2
-8
-7
April
2.6
-3
3
3
2
May
14.1
12
14
15
17
June
19.2
17
18
19
19
July
19.2
19
0
19
16
August
15.5
14
14
15
September
11.5
7
11
11
11
October
2.6
1
1
2
3
November
-8.3
-5
-10
-13
-7
December
-11.0
-16
-6
-13
-6
Average
1.2
-11.0
-1.8
2.3
3.9
2.2
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.