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
90.1
85
85
90
97
89
February
87.9
96
87
76
81
91
March
91.9
94
92
86
89
86
April
95.7
96
89
96
96
94
May
96.9
100
92
98
100
June
98.1
99
96
99
99
July
94.1
96
90
99
96
August
93.1
90
94
91
95
September
91.9
91
86
94
93
October
83.7
78
83
76
86
November
82.6
83
79
82
94
December
84.0
85
62
75
90
Average
92.3
93.2
91.0
88.1
91.6
93.4
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
-15.8
-18
-10
-14
-8
-22
February
-11.6
-8
-11
-11
-15
-13
March
-5.9
-4
-4
-3
-7
-7
April
5.7
8
0
4
5
5
May
14.9
15
13
14
17
June
20.3
20
22
21
18
July
22.4
24
22
22
20
August
18.4
21
19
17
19
September
12.3
10
13
10
13
October
2.5
0
2
1
1
November
-9.4
-4
-8
-14
-11
December
-11.0
-14
-13
-12
-10
Average
2.9
-6.5
3.9
4.5
3.0
2.5
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.