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
84.1
87
85
88
0
100
February
89.6
91
91
88
87
March
89.9
90
89
94
92
81
April
93.8
96
94
93
92
93
May
92.8
97
87
97
84
June
87.4
97
89
74
79
July
79.7
87
81
76
60
August
87.8
94
86
91
74
September
92.1
96
89
88
98
October
94.2
93
95
98
98
November
88.3
85
89
94
98
December
86.1
84
87
85
88
Average
88.0
91.2
91.3
89.0
87.6
84.4
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
-5.0
-4
-4
-8
0
-6
February
-2.1
-1
-4
-4
-1
March
2.0
4
0
2
4
4
April
9.5
11
8
10
11
10
May
16.8
17
16
16
17
June
22.6
19
23
25
22
July
26.1
26
26
27
24
August
24.5
25
25
25
25
September
20.9
21
23
21
20
October
12.5
14
13
13
13
November
4.0
6
3
9
5
December
-3.6
-2
-4
1
-3
Average
9.2
2.4
10.5
10.8
13.4
13.4
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.