Rock Island surfForecast / Kanagawa / Japan

information circle48hr Weather and Surf, issued 8 pm Thursday 21 May 2026 JST
Forecast update in hr  min  s Forecast update imminent
Rock Island surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.
Today's Rock Island sea temperature is
20.8° C
(Which is normal for this time of year)

How big are the waves at Rock Island today?

The current surf forecast for Rock Island at 1AM is: 0.9m 8s primary swell from a South direction and 0.1m 10s secondary swell from a Southeast direction (forecast issued at 08:00pm May 21). An open ocean swell of 0.4m 3s is not directed at the surf break. The wind direction is predicted to be offshore.

Time (JST) & DateWave HeightWave Period
Morning (22 May)2.5ft (0.7m)8s
Afternoon (22 May)1.5ft (0.5m)7s
Evening (22 May)1ft (0.3m)8s

Table - waves today at Rock Island. (Swell directed towards the surf break)


Updates in  hr  min  s Forecast update imminent

Short Range Forecast

Light rain (total 9mm), mostly falling on Thu night. Warm (max 20°C on Sun morning, min 13°C on Fri afternoon). Winds decreasing (strong winds from the N on Fri afternoon, calm by Sat night).

Thu
21
Friday
22
Saturday
23
Sunday
24
6 PM
9 PM
12 AM
3 AM
6 AM
9 AM
12 PM
3 PM
6 PM
9 PM
12 AM
3 AM
6 AM
9 AM
12 PM
3 PM
6 PM
9 PM
12 AM
3 AM
6 AM
9 AM
12 PM
3 PM
Rating
(10 max)
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
0
0
0
Swell
Height Map
Height MapHeight Map
Height MapHeight MapHeight Map
Height MapHeight MapHeight Map
Height MapHeight MapHeight Map
Wave
Height (m)
Direction
Period (s)
1.3
S
7
1.1
S
8
0.9
S
8
0.8
S
8
0.7
S
8
0.7
S
8
0.6
S
7
0.5
S
7
0.4
SSW
7
0.3
S
8
0.2
SSW
8
0.2
SSE
6
0.2
SSW
7
0.2
SSE
7
0.2
SSE
7
0.1
SE
11
0.2
ESE
6
0.3
SE
7
0.9
SE
6
0.9
SE
6
0.5
SE
6
0.6
SSE
6
0.6
SSE
6
0.6
SSE
6
Wave Graph
Metric surfscale
Energy kJ
183
142
95
76
57
55
40
28
18
10
6
4
5
5
5
5
5
7
56
62
18
26
26
26
Wind (km/h)
25
NE
25
NE
25
NE
30
NNE
30
N
40
N
45
N
45
N
40
NNE
40
NNE
30
NNE
35
NNE
30
NNE
30
NNE
25
NNE
10
NE
15
ESE
15
E
10
E
5
E
5
N
10
NE
10
ESE
15
SSE
cross-off
off
off
off
off
cross-off
off
off
off
off
off
off
off
off
off
off
cross
cross-off
cross-off
glassy
cross-off
cross-off
cross
cross-on
High Tide
9:23PM1.28m
7:05AM1.31m
10:14PM1.25m
7:58AM1.23m
11:05PM1.24m
9:12AM1.13m
Low Tide
2:07AM0.99m
2:39PM0.11m
3:10AM0.97m
3:31PM0.23m
4:29AM0.92m
light rain
cloud
cloud
light rain
light rain
light rain
light rain
light rain
light rain
cloud
part cloud
clear
cloud
cloud
part cloud
cloud
cloud
cloud
cloud
cloud
cloud
part cloud
part cloud
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:33
4:31
4:31
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:43
6:43
6:44
6:45
1
3
1
1
1
2
1
Temp °C
17
16
16
16
16
15
15
14
13
13
13
13
13
14
16
19
19
18
18
18
18
19
20
20
13
12
12
12
11
8
7
5
5
5
6
6
7
8
11
16
16
15
17
18
18
19
20
19
Swell 1
Height (m)
Direction
Period (s)
1.3
S
7
1.1
S
8
0.9
S
8
0.8
S
8
0.7
S
8
0.7
S
8
0.6
S
7
0.5
S
7
0.4
SSW
7
0.3
S
8
0.2
SSW
8
0.2
SSE
6
0.2
SSW
7
0.2
SSE
7
0.2
SSE
7
0.1
SE
11
0.2
ESE
6
0.3
SE
7
0.4
SE
6
0.5
SE
6
0.5
SE
6
0.6
SSE
6
0.6
SSE
6
0.6
SSE
6
Energy kJ
183
142
95
76
57
55
40
28
18
10
6
4
5
5
5
5
4
7
14
18
18
26
26
26
Swell 2
Height (m)
Direction
Period (s)
0.4
ESE
10
0.2
ESE
10
0.1
SE
11
0.1
SE
9
0.1
SE
10
0.1
SE
10
0.1
SE
10
0.1
SE
11
0.1
E
10
0.1
E
9
0.1
SE
6
0.1
SE
11
0.2
SSE
7
0.1
SE
11
0.1
SE
11
0.1
S
6
0.1
S
6
0.1
SE
11
0.1
E
12
0.1
E
12
0.1
E
12
0.1
E
12
0.1
E
12
0.1
E
10
Energy kJ
36
11
4
3
4
4
4
4
2
2
2
4
4
5
5
1
1
5
3
3
3
3
3
2
Swell 3
Height (m)
Direction
Period (s)
0.1
SE
11
0.1
E
11
0.1
E
6
0.3
SSE
7
0.1
E
11
0.1
E
11
0.1
SE
11
0.1
S
8
0.1
SE
11
0.1
SE
8
0.1
SE
7
0.1
SE
6
0.1
SE
11
0.1
S
6
0.1
SE
12
0.1
SE
10
0.1
SE
10
0.2
ESE
10
0.2
ESE
10
0.1
E
12
Energy kJ
5
3
1
9
2
2
4
1
5
2
2
1
5
1
6
4
4
10
10
3
Wind waves
Height (m)
Direction
Period (s)
0.4
NE
2
0.3
NE
3
0.4
NE
3
0.4
NE
3
0.4
NNE
3
0.7
NNE
3
0.9
NNE
4
0.9
NNE
4
1
NNE
4
0.9
NNE
4
0.8
NNE
4
0.8
NNE
4
0.7
NNE
4
0.7
NNE
4
0.5
NNE
4
0.4
NE
3
0.3
E
2
0.9
SE
6
0.9
SE
6
Energy kJ
1
1
2
2
3
10
21
23
32
26
17
16
12
12
7
3
1
56
62
Nearest Offshore or Glassy
Rating
(10 max)
4
1
1
2
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
3
2
2
1
Distance (km)
92
0
8
487
38
487
145
487
487
552
552
552
798
804
885
885
885
64
0
0
16
38
38
64
Best forecast wave conditions in Kanagawa
Rating
(10 max)
1
1
1
1
1
3
Best forecast wave conditions in Japan
Rating
(10 max)
4
2
4
2
2
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
3
2
2
1
Header Global
Rating
(10 max)
5
5
5
5
5
5
5
7
7
7
6
6
7
8
6
7
8
8
7
7
6
6
5
5
  • Map Icons:
  • Break
  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
Map placeholder

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