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
79.4
59
85
70
86
82
February
83.9
94
80
63
67
94
March
82.3
14
88
96
91
88
April
88.8
40
100
94
96
May
97.1
100
86
98
100
June
98.0
98
93
100
99
July
96.4
88
94
99
100
August
97.3
100
93
99
96
September
93.3
94
98
93
78
October
89.0
84
89
91
87
November
84.4
63
82
90
95
December
82.9
67
87
61
97
Average
86.7
51.2
83.0
88.1
91.9
93.6
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
-12.7
-11
-8
-8
-5
-24
February
-6.3
-5
-7
-6
-5
-9
March
-2.1
-1
-3
-1
-4
-4
April
4.9
1
4
6
5
May
12.8
12
11
13
15
June
18.7
15
20
19
17
July
20.2
19
20
20
18
August
16.6
19
16
16
18
September
11.0
10
9
10
10
October
3.2
2
2
2
3
November
-7.6
-3
-6
-15
-7
December
-9.3
-9
-12
-11
-9
Average
3.0
-6.3
3.3
3.6
3.9
2.8
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.