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
83.9
82
80
95
87
80
February
87.4
82
94
88
92
86
March
90.2
83
81
98
93
95
April
94.0
83
96
96
91
May
97.8
97
97
99
100
June
99.7
98
100
100
100
July
92.3
81
99
99
98
August
90.9
71
98
92
95
September
91.2
91
93
90
90
October
78.0
85
78
65
81
November
77.4
81
71
92
69
December
84.0
87
76
94
89
Average
89.1
82.5
84.4
92.4
91.7
91.0
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
-22.1
-27
-15
-23
-19
-29
February
-19.5
-18
-17
-20
-24
-20
March
-7.2
-7
-7
-7
-10
-8
April
2.3
-1
3
4
3
May
15.4
16
14
13
17
June
21.9
21
21
23
22
July
23.9
26
23
24
20
August
18.4
21
19
17
21
September
11.4
11
12
11
11
October
-1.9
1
-1
0
-1
November
-13.7
1
-14
-15
-14
December
-17.4
-7
-16
-20
-17
Average
-1.4
-18.6
4.2
1.5
0.5
0.6
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.