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
85.4
77
79
99
93
94
February
91.4
89
91
91
90
99
March
93.5
93
86
95
95
100
April
96.0
94
96
98
100
May
97.7
100
96
99
100
June
99.9
100
100
100
100
July
99.7
100
100
100
100
August
99.7
100
99
100
100
September
99.6
100
100
100
98
October
97.2
97
99
95
98
November
94.6
93
92
98
98
December
90.4
94
86
88
90
Average
94.8
86.3
94.0
96.7
96.3
97.4
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
-1.8
1
-2
-1
0
-3
February
0.7
3
-2
-1
0
-4
March
6.3
7
1
5
7
6
April
14.3
9
23
14
5
May
19.9
21
23
20
9
June
25.4
23
25
29
18
July
29.6
30
26
32
30
August
28.4
29
25
29
31
September
23.6
25
23
26
18
October
14.5
16
20
15
11
November
7.5
8
4
10
9
December
1.1
2
-2
4
1
Average
12.8
3.7
13.2
14.7
14.5
13.9
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.