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
January
78.5
87
71
70
86
February
82.3
81
83
83
85
March
86.6
79
84
83
90
April
91.1
92
94
89
89
May
94.7
94
98
97
95
June
90.3
86
84
94
94
July
89.6
83
84
94
92
August
90.8
88
92
84
89
September
91.6
92
90
91
93
October
92.1
94
95
83
94
November
88.2
79
93
90
85
December
80.5
65
74
84
89
Average
88.7
85.5
87.2
87.4
90.4
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
January
1.3
0.5
3.7
0.2
0.6
February
1.7
1.8
0.6
2.2
0.6
March
4.8
7.0
3.7
6.4
7.0
April
11.1
10.6
12.6
11.0
12.0
May
17.3
18.5
17.3
19.3
17.1
June
22.6
23.3
21.0
22.1
25.5
July
26.4
27.1
27.3
27.1
24.6
August
25.6
25.1
23.6
26.0
26.5
September
21.4
21.1
22.1
20.8
21.8
October
15.8
15.8
17.0
17.3
16.1
November
8.8
8.8
6.7
10.5
9.0
December
3.4
3.2
4.9
4.5
4.2
Average
13.4
13.6
13.4
14.3
13.8
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.
Minimum temperatures (°C)
Month
Average
2024
2023
2022
2021
January
-7.7
-6.4
-4.9
-11.8
-5.4
February
-8.9
-7.7
-10.1
-8.2
-7.9
March
-4.6
-1.7
-4.6
-4.9
-5.5
April
1.7
1.0
2.2
2.0
2.5
May
5.9
7.2
4.5
6.5
5.5
June
11.6
12.6
11.5
11.1
13.3
July
15.7
16.3
17.8
15.0
14.9
August
15.3
14.5
14.5
16.1
16.1
September
11.0
10.4
11.8
10.9
12.3
October
6.0
5.2
7.2
5.9
6.9
November
1.0
3.1
-1.1
1.8
0.6
December
-4.4
-6.7
-3.7
-2.3
-5.9
Average
4.1
4.4
4.3
4.1
4.4
Average lowest temperature per day
The minimum temperature is typically observed just before sunrise.
Precipitation (%)
Month
Average
2024
2023
2022
2021
January
40.7
37
40
50
31
February
30.9
36
31
37
21
March
30.7
40
35
37
23
April
23.5
18
11
30
26
May
15.1
10
11
9
15
June
15.8
19
29
11
6
July
10.6
13
15
7
14
August
9.5
10
14
15
9
September
10.1
12
7
8
12
October
12.6
10
14
14
10
November
25.6
44
21
22
29
December
35.3
43
33
42
25
Average
20.3
22.5
20.6
21.2
17.3
Precipitation during daylight period
Percentage of observations with observed rain, drizzle, snow or hail. Only observations between sunrise and sunset are taken into account.
Wind speed (knots)
Month
Average
2024
2023
2022
2021
January
9.6
11
9
9
9
February
10.3
10
10
11
10
March
11.3
11
10
11
12
April
10.3
9
9
10
11
May
8.9
8
11
9
9
June
8.0
8
8
7
9
July
6.9
7
6
9
7
August
7.2
7
7
7
6
September
7.6
8
7
7
8
October
8.3
8
7
7
8
November
9.9
10
8
11
9
December
9.5
8
9
11
11
Average
8.8
8.5
8.2
8.8
8.9
Average wind speed
Excluding wind gusts. Only observations between sunrise and sunset are taken into account.
Prevailing wind direction
Month
2024
2023
2022
2021
January
290°
330°
278°
339°
February
296°
311°
256°
282°
March
270°
342°
265°
264°
April
321°
284°
282°
319°
May
347°
281°
288°
276°
June
258°
352°
268°
250°
July
248°
239°
251°
261°
August
255°
242°
263°
256°
September
292°
294°
273°
247°
October
261°
265°
228°
302°
November
306°
264°
266°
266°
December
259°
265°
026°
280°
Prevailing wind direction
Average wind direction, weighed by wind speed. Only observations between sunrise and sunset are taken into account.