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
87.3
89
94
81
89
83
February
88.3
78
77
86
90
96
March
95.3
94
96
97
95
96
April
97.3
97
92
100
100
May
97.1
99
95
97
99
June
98.1
99
98
98
98
July
95.9
90
95
97
100
August
97.9
97
99
98
99
September
94.2
98
91
97
91
October
86.9
83
78
97
81
November
83.8
88
81
88
78
December
88.1
79
96
91
90
Average
92.7
87.4
92.1
91.1
95.0
93.5
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
-3.8
-4
0
-2
-1
-5
February
-2.6
0
0
2
-3
2
March
5.2
7
4
8
6
4
April
10.5
10
8
13
11
May
18.1
22
14
16
18
June
20.4
23
21
22
18
July
22.9
25
23
24
20
August
23.3
25
25
23
19
September
17.0
18
19
16
17
October
9.1
10
13
8
7
November
1.7
4
-2
3
2
December
-4.4
1
-9
-10
1
Average
9.0
0.9
11.8
10.5
9.8
9.5
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
-9.9
-10
-5
-9
-6
-11
February
-11.6
-9
-8
-6
-11
-7
March
-6.5
-5
-8
-2
-3
-6
April
-2.6
-1
-3
-1
-2
May
4.2
5
3
3
4
June
7.2
7
7
8
7
July
9.8
10
10
11
10
August
9.2
10
10
9
9
September
5.3
4
5
6
6
October
0.4
0
3
0
0
November
-4.5
-1
-8
-3
-4
December
-10.8
-4
-16
-17
-4
Average
-2.9
-8.0
0.7
0.1
-1.7
0.2
Average lowest temperature per day
The minimum temperature is typically observed just before sunrise.
Precipitation (%)
Month
Average
2024
2023
2022
2021
2020
January
28.0
31
24
30
27
40
February
23.3
21
38
28
31
11
March
13.7
13
11
10
17
17
April
12.2
22
16
6
9
May
12.1
3
18
18
12
June
11.7
5
16
11
15
July
13.4
8
23
14
19
August
11.0
4
13
11
27
September
15.1
11
7
22
21
October
16.5
22
17
10
12
November
27.5
23
22
34
31
December
22.3
29
10
27
26
Average
16.8
20.9
15.1
17.2
17.6
19.1
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
4.1
4
4
4
5
5
February
4.1
4
4
4
5
4
March
4.7
5
5
5
5
5
April
5.1
5
5
5
5
May
4.3
5
4
4
5
June
4.0
4
4
3
4
July
3.6
4
4
4
4
August
3.8
4
4
5
4
September
3.9
4
3
5
4
October
4.0
4
4
5
3
November
4.1
4
5
5
4
December
3.9
4
4
3
4
Average
4.1
4.0
4.1
4.2
4.4
4.1
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
148°
146°
158°
154°
148°
February
153°
165°
173°
154°
169°
March
167°
165°
169°
162°
167°
April
169°
168°
179°
194°
May
332°
250°
320°
186°
June
332°
320°
302°
343°
July
317°
335°
324°
324°
August
311°
301°
303°
148°
September
178°
266°
159°
196°
October
166°
165°
164°
204°
November
153°
146°
151°
158°
December
154°
147°
149°
147°
Prevailing wind direction
Average wind direction, weighed by wind speed. Only observations between sunrise and sunset are taken into account.