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
82.5
81
66
90
93
82
February
87.3
79
81
92
91
92
March
87.8
87
74
82
94
94
April
94.2
87
94
97
93
May
97.3
99
94
97
100
June
99.5
99
99
100
100
July
99.6
99
99
100
100
August
99.1
99
99
98
100
September
98.8
99
98
100
99
October
93.9
95
91
96
96
November
92.6
80
86
100
99
December
84.8
77
63
90
90
Average
92.4
82.5
88.0
91.3
96.5
95.7
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
-2.8
1
-3
-2
-1
-1
February
0.5
3
-3
-1
1
-3
March
7.2
8
1
6
9
7
April
14.4
10
15
16
15
May
20.4
22
19
21
22
June
27.5
25
27
30
27
July
32.2
32
32
33
32
August
30.9
30
31
30
33
September
26.2
26
27
27
26
October
15.7
17
17
16
17
November
8.8
9
5
12
10
December
0.8
2
-5
4
1
Average
13.9
3.8
14.0
14.8
16.4
15.5
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.