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
18.5
24
18
17
33
14
February
20.8
18
27
31
13
13
March
18.7
12
27
17
23
53
April
23.1
31
19
20
34
May
37.5
56
24
37
41
June
26.4
19
30
20
45
July
31.3
26
42
6
32
August
25.5
15
26
31
26
September
28.6
46
14
16
25
October
23.6
25
33
23
19
November
18.9
22
19
14
23
December
11.7
18
8
10
12
Average
23.1
17.5
28.2
24.4
20.7
28.0
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
-10.5
-8
-5
-12
-10
-8
February
-10.7
-7
-8
-8
-12
-10
March
-8.7
-3
-6
-5
-6
-7
April
-2.4
2
-1
-2
-5
May
5.2
5
9
5
4
June
9.4
10
9
11
10
July
12.8
14
13
11
14
August
11.6
11
14
13
11
September
9.1
11
9
8
9
October
4.0
4
6
5
2
November
-5.9
-5
-1
-5
-2
December
-8.6
-3
-6
-7
-7
Average
0.2
-6.0
2.4
2.4
0.9
0.9
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.