🌊 Seastate

The European sea atlas

Share of days when waves passed 2.5 m, the height at which most people stop enjoying themselves and tender calls start being cancelled. 2015 to 2024.

Days above 2.5 mSettled 0-10%Mostly calm 10-25%Mixed 25-45%Often lively 45-65%Frequently rough 65%+
 JFMAMJJASOND
The Mediterranean
Alboran Sea
13
23
20
12
2
2
1
0
3
3
9
10
Balearic Sea
17
12
11
4
1
0
0
1
3
4
13
12
Gulf of Lion
42
34
32
17
13
7
10
9
12
17
31
28
Ligurian Sea
13
10
10
3
1
0
1
0
3
4
14
9
Tyrrhenian Sea
19
18
13
4
2
0
2
1
4
4
17
16
Sardinian Sea
34
30
25
13
6
2
4
4
7
12
27
27
Strait of Sicily
19
15
14
8
4
1
1
1
3
6
11
20
Ionian Sea
27
24
15
7
2
1
1
0
3
8
18
20
Adriatic Sea
8
9
5
2
1
0
0
0
2
2
7
6
Aegean Sea
25
23
15
5
2
0
1
0
6
6
10
16
Cretan Sea
28
23
18
7
2
0
1
0
3
3
10
19
Levantine Sea
28
14
12
5
2
0
0
0
1
1
6
13
Atlantic and Iberia
Gulf of Cadiz
22
29
28
17
7
2
1
2
4
12
16
25
Portuguese Atlantic
67
77
75
47
27
20
9
16
30
48
65
71
Madeira and Canaries
29
36
37
20
9
2
2
2
4
15
26
29
Bay of Biscay
72
83
77
40
24
16
8
14
33
55
72
78
Celtic Sea
75
90
78
42
26
25
18
27
43
61
75
83
English Channel
37
35
29
9
6
3
3
6
11
20
35
46
Irish Sea
29
31
20
7
3
3
2
5
8
15
25
39
North Sea and Baltic
Southern North Sea
43
37
21
12
6
4
5
6
17
25
37
39
Central North Sea
60
60
40
26
14
12
10
12
30
40
52
59
Northern North Sea
79
76
63
40
20
16
10
15
46
58
65
80
Skagerrak
41
35
20
12
5
9
9
8
19
26
29
32
Kattegat
15
9
3
3
0
1
3
1
4
7
6
10
Western Baltic
14
12
6
2
0
0
1
1
4
8
8
9
Central Baltic
37
27
14
8
1
3
3
3
14
21
23
32
Gulf of Finland
7
4
2
1
0
0
0
0
4
4
6
5
Norway and the far north
Norwegian Sea
91
90
83
54
37
24
11
24
52
65
76
88
Lofoten and Vesteralen
30
29
29
8
4
3
1
3
8
13
23
29
Barents Sea approach
68
70
62
42
28
16
6
12
30
46
50
63
Faroe and Iceland waters
92
90
82
56
38
24
13
21
54
69
79
86

Every cell is a decade of daily records. Pick a sea to see it week by week.

Where these numbers come from

Significant wave height, wave period, wind and air temperature from ERA5 reanalysis, 2015 to 2024, sampled at open-water points in each sea and pooled by week of the year. 10 years behind every figure shown.

This is climate, not a forecast. It says what that water usually does in that week, which is the only thing knowable when you are booking months ahead.