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
81.6
88
74
77
89
77
February
70.2
72
68
54
74
84
March
84.6
70
84
91
89
85
April
91.5
92
96
90
85
May
95.3
89
97
99
100
June
94.2
92
85
91
97
July
85.7
87
82
89
August
84.1
85
74
63
93
September
83.0
74
77
86
91
October
82.0
89
67
81
92
November
74.5
74
62
92
80
December
75.4
72
77
63
87
Average
83.7
75.2
82.9
79.5
86.1
90.0
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
-13.1
-12
-10
-12
-9
-24
February
-7.3
-5
-7
-7
-9
-10
March
-2.1
-2
-2
1
-3
-7
April
5.7
1
6
5
6
May
13.9
11
15
16
16
June
19.3
16
22
17
19
July
20.3
19
19
19
August
17.4
18
16
14
20
September
11.4
10
12
10
12
October
4.4
3
4
2
5
November
-6.3
-3
-6
-13
-6
December
-10.4
-13
-8
-8
-9
Average
1.9
-7.8
3.4
4.7
-1.1
3.8
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.