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
92.2
95
85
95
94
95
February
92.8
96
86
93
95
92
March
94.4
95
92
94
93
93
April
94.5
95
95
94
92
May
97.8
97
98
98
100
June
99.2
99
100
99
99
July
99.6
99
100
100
100
August
95.5
99
100
100
100
September
97.0
100
100
98
98
October
94.6
96
99
95
90
November
94.6
98
90
98
98
December
93.7
96
91
91
95
Average
95.6
95.3
95.4
96.5
96.3
96.1
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
0.0
1
-2
0
1
0
February
0.8
4
-1
-1
0
-1
March
5.6
6
1
6
7
7
April
11.6
9
12
12
12
May
17.6
19
17
18
19
June
24.5
21
25
27
24
July
29.4
29
30
30
29
August
27.6
27
28
27
30
September
23.2
23
24
24
23
October
13.0
15
14
14
15
November
6.8
8
3
10
8
December
1.3
3
0
3
1
Average
12.3
3.2
12.5
13.6
14.5
13.9
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
-10.2
-10
-10
-11
-10
-8
February
-9.0
-6
-12
-12
-8
-12
March
-5.0
-4
-9
-6
-5
-3
April
-3.8
-3
-2
-4
-3
May
2.6
3
2
2
3
June
7.3
7
7
9
7
July
11.3
11
12
13
10
August
9.7
10
11
9
10
September
5.5
6
7
5
4
October
-2.9
0
-1
1
-1
November
-5.2
-5
-8
-2
-5
December
-9.0
-9
-10
-6
-10
Average
-2.9
-7.1
-1.1
-1.4
0.5
-1.4
Average lowest temperature per day
The minimum temperature is typically observed just before sunrise.
Precipitation (%)
Month
Average
2024
2023
2022
2021
2020
January
9.7
8
19
8
8
8
February
8.3
6
14
9
7
9
March
8.1
10
7
12
6
10
April
6.3
6
6
5
9
May
4.9
6
6
3
2
June
1.9
3
1
2
1
July
1.6
1
3
1
2
August
1.6
2
1
4
0
September
2.5
1
3
4
2
October
5.1
7
3
5
2
November
6.7
5
12
4
3
December
7.8
4
11
10
10
Average
5.5
7.9
6.0
5.7
4.5
4.5
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
8.8
7
8
8
8
12
February
11.1
10
11
10
14
9
March
10.1
10
10
9
10
11
April
11.4
10
14
10
11
May
8.9
8
11
9
9
June
9.3
8
10
7
10
July
7.5
8
8
6
9
August
7.7
8
7
9
7
September
9.3
9
8
8
9
October
9.7
9
9
9
11
November
10.4
9
10
12
11
December
9.0
7
10
12
8
Average
9.4
9.3
8.7
9.4
9.4
9.7
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
220°
223°
209°
217°
229°
February
223°
219°
221°
243°
237°
March
224°
221°
238°
242°
230°
April
239°
243°
256°
246°
May
239°
241°
230°
237°
June
219°
227°
227°
228°
July
247°
214°
229°
232°
August
241°
252°
222°
254°
September
215°
227°
236°
242°
October
238°
246°
227°
243°
November
235°
213°
231°
218°
December
223°
226°
218°
220°
Prevailing wind direction
Average wind direction, weighed by wind speed. Only observations between sunrise and sunset are taken into account.