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
79.8
81
78
75
83
85
February
83.3
82
83
94
85
80
March
89.2
85
87
85
99
92
April
90.4
98
88
77
97
93
May
95.8
98
87
99
98
June
98.5
98
100
100
99
July
97.6
100
100
100
100
August
95.7
98
97
100
100
September
96.4
97
99
100
100
October
97.1
99
97
97
98
November
91.4
94
78
92
93
December
83.7
79
78
75
86
Average
91.4
86.7
91.2
89.6
95.0
94.3
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
-5.9
-3
-5
-7
-5
-2
February
-3.9
0
-5
-4
-2
-3
March
2.2
2
-1
3
1
3
April
8.6
9
5
8
10
8
May
16.1
17
14
16
17
June
21.5
19
22
26
20
July
27.1
28
28
28
26
August
25.8
24
26
25
28
September
21.4
19
24
22
23
October
12.1
13
14
12
15
November
4.2
6
-1
6
5
December
-3.4
-2
-4
0
-4
Average
9.8
1.9
10.0
10.8
11.8
11.3
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.