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
84.8
86
70
87
88
89
February
90.4
98
83
85
84
91
March
92.4
93
86
86
90
92
April
96.9
87
100
99
95
May
97.2
99
95
98
97
June
96.0
99
91
95
95
July
93.1
94
92
99
98
August
93.9
85
92
96
97
September
91.3
93
86
93
90
October
84.9
86
79
72
87
November
85.0
79
79
88
91
December
81.3
81
74
80
85
Average
91.9
92.2
88.7
89.1
91.9
93.2
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
-19.4
-11
-16
-21
-17
-26
February
-15.8
-14
-13
-13
-18
-16
March
-5.6
-2
-5
-4
-7
-7
April
5.9
2
4
6
6
May
15.9
15
14
15
18
June
20.8
21
22
22
19
July
23.1
26
22
23
22
August
19.4
23
19
20
19
September
13.3
12
14
11
14
October
1.1
1
1
-1
1
November
-13.0
-10
-12
-18
-16
December
-18.6
-17
-17
-17
-17
Average
1.3
-9.1
3.2
3.2
1.7
1.6
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.