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
84.5
68
82
93
93
86
February
82.5
90
71
73
79
90
March
92.1
95
91
94
88
87
April
94.1
88
99
94
87
May
95.9
93
89
99
99
June
93.7
94
87
100
88
July
89.7
93
79
95
93
August
84.5
74
86
83
89
September
87.7
83
81
90
88
October
82.6
85
76
73
84
November
78.5
83
73
88
84
December
80.1
80
65
75
97
Average
88.4
85.7
85.9
83.9
89.8
89.5
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
-18.2
-19
-14
-17
-13
-26
February
-13.7
-11
-13
-13
-17
-14
March
-5.4
-4
-5
-3
-8
-7
April
5.3
0
5
5
5
May
16.7
17
15
16
19
June
22.3
21
24
23
21
July
23.9
25
23
24
21
August
19.4
21
21
18
21
September
13.6
12
14
12
14
October
3.1
0
2
2
3
November
-10.3
-6
-10
-15
-13
December
-14.7
-16
-14
-14
-8
Average
2.2
-12.5
3.7
4.4
3.3
3.5
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.