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
87.6
88
88
88
90
February
87.3
90
88
88
90
March
86.2
83
84
89
86
April
90.0
92
91
93
83
May
91.0
92
90
90
June
98.1
99
96
98
July
99.7
100
100
100
August
98.9
98
98
100
100
September
96.1
97
96
99
91
October
92.5
93
93
96
94
November
93.5
97
92
98
94
December
90.2
92
89
87
91
Average
92.7
88.2
93.2
92.8
93.2
92.2
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
0.5
0
-1
3
1
February
1.4
2
1
1
0
March
4.7
3
1
6
5
April
9.1
10
8
9
9
May
13.4
14
15
14
June
20.8
18
21
23
July
24.5
26
23
25
August
22.9
23
22
23
21
September
20.0
19
21
21
19
October
12.1
13
11
12
15
November
7.0
6
4
9
7
December
2.6
3
0
3
2
Average
9.9
3.7
11.0
11.8
12.0
10.6
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.
Minimum temperatures (°C)
Month
Average
2024
2023
2022
2021
2020
January
-6.2
-6
-7
-5
-6
February
-6.2
-5
-7
-8
-7
March
-4.7
-3
-6
-4
-4
April
-1.6
0
-2
-1
-1
May
4.1
5
4
4
June
9.7
8
10
11
July
12.9
13
13
13
August
12.1
12
12
12
16
September
9.4
9
10
10
8
October
2.6
3
3
3
4
November
-1.3
-1
-5
1
-1
December
-4.1
-4
-6
-3
-5
Average
2.3
-4.4
1.9
2.1
2.8
1.6
Average lowest temperature per day
The minimum temperature is typically observed just before sunrise.
Precipitation (%)
Month
Average
2024
2023
2022
2021
2020
January
14.0
12
13
12
13
February
14.8
14
14
12
14
March
15.3
20
19
14
15
April
9.2
6
10
9
13
May
7.3
7
10
6
June
3.4
4
4
4
July
3.6
2
6
4
August
3.2
3
4
2
0
September
3.4
2
6
2
5
October
7.1
10
7
5
7
November
6.2
5
7
3
8
December
12.7
11
15
21
10
Average
7.8
12.5
8.0
8.4
7.9
7.3
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
2020
January
7.3
6
9
7
8
February
9.1
9
8
8
10
March
7.1
7
8
6
6
April
8.1
9
8
10
7
May
6.5
6
8
5
June
6.0
7
6
5
July
4.3
5
4
4
August
5.1
6
4
5
8
September
5.5
6
5
6
5
October
7.5
6
7
8
10
November
7.8
6
7
9
8
December
7.3
6
9
10
5
Average
6.5
7.5
6.5
6.6
6.7
6.9
Average wind speed
Excluding wind gusts. Only observations between sunrise and sunset are taken into account.
Prevailing wind direction
Month
2024
2023
2022
2021
2020
January
277°
264°
269°
260°
February
278°
261°
252°
273°
March
261°
258°
244°
235°
April
266°
265°
256°
245°
May
196°
244°
221°
June
253°
218°
184°
July
256°
150°
143°
August
181°
149°
197°
219°
September
191°
165°
204°
201°
October
252°
223°
229°
259°
November
262°
251°
259°
261°
December
282°
264°
263°
261°
Prevailing wind direction
Average wind direction, weighed by wind speed. Only observations between sunrise and sunset are taken into account.