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
2021
2020
January
86.1
76
87
91
February
86.2
82
94
82
March
81.3
84
82
74
April
85.5
85
75
May
95.1
99
98
June
100.0
0
100
100
July
91.2
96
84
93
August
81.7
69
77
85
September
86.8
77
85
91
October
85.8
79
69
86
November
80.9
77
80
82
December
81.8
83
77
Average
84.9
81.5
77.7
85.0
86.0
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
2021
2020
January
-18.3
-18
-13
-23
February
-16.9
-11
-21
-20
March
-8.4
-8
-12
-9
April
0.4
-1
0
May
13.6
14
14
June
19.5
19
18
19
July
20.6
24
18
18
August
16.4
17
16
19
September
10.4
9
9
9
October
1.1
0
-3
1
November
-10.3
-6
-25
-9
December
-13.5
-15
-13
Average
0.8
-13.6
4.5
-3.7
0.6
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.