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
74.8
58
84
71
91
65
February
87.1
81
89
89
91
91
March
92.5
93
88
95
97
91
April
96.4
99
96
95
100
98
May
98.3
99
99
99
97
June
98.3
100
97
100
96
July
99.8
100
100
100
100
August
97.5
93
100
96
100
September
92.8
100
88
97
82
October
87.8
98
90
36
93
November
89.4
89
84
86
91
December
80.5
71
81
82
86
Average
90.8
79.7
92.3
91.9
90.2
91.5
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
0.7
-1
1
0
2
2
February
1.9
4
2
3
1
5
March
7.9
9
6
9
10
8
April
12.7
14
12
10
16
13
May
20.1
24
16
19
19
June
23.7
26
23
28
21
July
29.5
30
30
33
27
August
28.9
29
31
28
29
September
21.8
22
24
21
23
October
13.0
15
16
13
13
November
4.5
5
1
6
5
December
0.9
3
-2
0
2
Average
12.9
6.2
14.6
13.8
14.7
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
2020
January
-4.5
-5
-2
-5
-2
-2
February
-5.6
0
-4
-5
-5
-3
March
-2.5
-1
-3
0
-2
-1
April
1.3
2
1
0
1
1
May
6.4
9
5
5
6
June
9.3
10
10
11
9
July
10.5
11
12
12
10
August
10.7
12
12
11
10
September
6.8
8
8
6
7
October
1.7
3
4
3
2
November
-2.8
-2
-5
1
0
December
-4.5
-1
-6
-4
-3
Average
2.2
-2.9
3.5
2.6
3.1
2.9
Average lowest temperature per day
The minimum temperature is typically observed just before sunrise.
Precipitation (%)
Month
Average
2024
2023
2022
2021
2020
January
23.0
31
12
20
20
46
February
20.9
28
22
14
18
12
March
15.7
18
14
15
10
18
April
13.3
6
10
13
6
6
May
8.4
7
14
6
14
June
7.2
4
14
5
9
July
1.7
0
2
1
3
August
1.8
4
1
3
1
September
4.6
5
3
7
3
October
8.0
4
13
7
10
November
18.5
21
19
22
19
December
21.2
24
17
25
18
Average
12.4
21.4
10.2
11.4
9.9
12.3
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
4.3
5
4
3
4
3
February
5.5
5
5
4
6
4
March
5.1
4
6
4
5
7
April
5.5
6
5
6
6
6
May
5.5
5
5
7
6
June
4.9
4
5
5
5
July
4.7
5
4
5
5
August
4.6
5
4
5
4
September
4.8
5
5
4
4
October
4.4
5
4
4
5
November
4.4
4
6
4
5
December
3.7
3
4
5
3
Average
4.8
4.9
4.6
4.6
4.9
4.7
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
036°
051°
207°
020°
215°
February
043°
015°
277°
288°
204°
March
100°
048°
170°
189°
059°
April
164°
187°
065°
112°
135°
May
081°
178°
116°
071°
June
180°
172°
136°
189°
July
157°
161°
144°
182°
August
134°
123°
154°
185°
September
052°
070°
186°
149°
October
050°
196°
031°
217°
November
046°
030°
220°
221°
December
056°
355°
243°
254°
Prevailing wind direction
Average wind direction, weighed by wind speed. Only observations between sunrise and sunset are taken into account.