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
88.6
86
84
90
90
90
February
91.2
85
94
92
95
94
March
93.6
92
99
94
92
86
April
93.6
82
100
94
90
May
97.7
97
96
97
100
June
97.4
98
98
95
98
July
91.8
57
96
99
95
August
90.6
67
98
92
93
September
91.4
80
94
92
95
October
77.0
58
73
70
89
November
83.5
77
95
82
85
December
91.1
94
81
86
86
Average
91.3
88.3
81.1
93.6
91.7
92.8
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
-21.4
-25
-18
-24
-20
-25
February
-19.9
-16
-22
-20
-25
-19
March
-11.6
-12
-11
-13
-13
-11
April
-1.4
-2
-1
0
-1
May
14.6
18
14
13
11
June
20.7
23
20
23
21
July
24.0
28
25
25
21
August
20.3
23
24
20
20
September
13.2
15
15
13
13
October
1.3
2
2
1
0
November
-13.8
-8
-12
-15
-14
December
-19.5
-16
-20
-22
-19
Average
-1.0
-18.4
2.9
1.6
0.0
-1.8
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.