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
2025
2024
2023
2022
2021
January
72.7
82
59
64
87
74
February
82.9
81
91
87
80
85
March
86.6
92
83
82
89
98
April
90.6
93
91
91
94
May
92.4
86
95
97
90
94
June
94.1
95
95
85
98
93
July
94.3
93
92
96
92
August
93.9
95
91
92
97
September
88.6
90
84
93
90
October
87.0
97
89
92
75
November
87.3
85
91
89
92
December
78.8
77
59
92
84
Average
88.1
87.8
88.8
85.6
90.9
89.6
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
2025
2024
2023
2022
2021
January
-1.8
-3.2
-1.0
2.7
-3.2
-1.9
February
2.5
-1.1
6.9
4.9
1.3
-2.1
March
7.9
11.5
9.8
6.5
7.9
12.0
April
13.9
16.1
15.6
11.6
15.1
May
20.8
19.0
23.1
21.6
21.6
20.3
June
26.1
27.0
26.3
26.1
26.3
26.6
July
27.8
27.0
27.6
28.5
26.6
August
26.8
26.1
25.1
27.3
28.1
September
23.4
24.3
22.6
23.0
23.6
October
16.5
19.3
16.0
16.8
17.8
November
8.2
10.5
8.9
10.5
7.5
December
3.3
2.5
6.2
3.2
5.2
Average
14.4
10.9
15.9
15.3
15.0
15.2
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.
Minimum temperatures (°C)
Month
Average
2025
2024
2023
2022
2021
January
-7.8
-9.3
-5.0
-2.0
-12.8
-5.0
February
-6.3
-8.5
-3.2
-4.3
-8.0
-10.0
March
-2.5
0.1
0.4
-2.6
-2.0
-1.5
April
3.5
5.5
4.2
2.6
3.9
May
9.4
8.5
11.5
7.5
10.6
7.9
June
14.6
15.9
15.9
11.9
14.0
16.1
July
16.7
16.8
17.0
15.0
16.8
August
16.2
16.0
15.5
16.8
17.6
September
13.1
12.8
13.5
13.3
12.8
October
7.1
6.7
8.0
5.5
10.5
November
0.5
3.2
-1.5
1.7
-1.7
December
-3.5
-3.2
1.3
-2.8
-2.5
Average
5.1
1.7
6.5
6.0
5.0
5.8
Average lowest temperature per day
The minimum temperature is typically observed just before sunrise.
Precipitation (%)
Month
Average
2025
2024
2023
2022
2021
January
17.7
25
25
20
14
15
February
13.2
13
4
9
20
18
March
10.6
10
10
16
9
1
April
10.8
11
15
12
9
May
7.6
8
5
5
10
8
June
5.1
6
4
7
4
8
July
4.4
3
6
4
7
August
4.1
6
6
3
1
September
4.9
3
4
4
10
October
9.4
2
12
6
12
November
10.8
14
8
12
9
December
11.8
16
17
4
8
Average
9.0
11.5
7.8
9.9
8.3
8.3
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
2025
2024
2023
2022
2021
January
7.4
9
7
6
7
6
February
8.1
8
7
9
8
8
March
8.5
10
9
8
9
9
April
8.4
9
7
9
8
May
6.6
7
6
6
7
6
June
6.0
6
6
5
6
6
July
5.1
5
5
6
6
August
5.0
5
5
5
4
September
5.4
5
4
5
6
October
6.7
7
6
7
6
November
7.5
8
7
8
7
December
7.3
8
6
7
8
Average
6.9
7.7
6.6
6.1
7.0
6.6
Average wind speed
Excluding wind gusts. Only observations between sunrise and sunset are taken into account.
Prevailing wind direction
Month
2025
2024
2023
2022
2021
January
254°
240°
230°
241°
257°
February
255°
238°
234°
226°
244°
March
225°
228°
258°
247°
236°
April
242°
227°
223°
244°
May
350°
228°
320°
162°
236°
June
228°
231°
022°
241°
220°
July
243°
247°
244°
271°
August
266°
267°
241°
234°
September
075°
180°
248°
244°
October
238°
246°
222°
222°
November
228°
233°
219°
230°
December
234°
227°
206°
216°
Prevailing wind direction
Average wind direction, weighed by wind speed. Only observations between sunrise and sunset are taken into account.