Rock Island Surf Break

Lat Long: 35.29° N 139.55° E

Rock Island Surf Forecast and Surf Report

Issued: 2 am 09 Aug 2026 (local time)

Forecast update in  hr  min

Today's Rock Island sea temperature is
27.0° C
0.2° 

Rock Island surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Rock Island surf forecast from 8 Aug 2026:

  • Best quality surf: Sunday 9 Aug, 9AM (local time) - 2.5ft (0.7m), 10s period, SSW swell with glassy winds.
  • Most powerful swell: Tuesday 11 Aug, 6PM (local time) - 3ft (0.9m), 10s period, SSW swell with 155 kJ wave energy.
  • Next surfable swell (1★+): Sunday 9 Aug, 9AM (local time) - 2.5ft (0.7m), 10s period with SSW swell.

Best Forecast Surf Conditions for Rock Island this week:

The surf forecast for Rock Island over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Sunday (Aug 09) at 9AM. The primary swell is predicted to be 0.7m and 10s period with a secondary swell of 0.3m and 13s. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Rock Island in the next 16 days are 0.9m 10s and forecast to arrive on Tuesday (Aug 11) at 6PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.7m 3s period and expected on Thursday (Aug 13) at 12PM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 9AM (Sun 9th Aug)2.5ft (0.7m) 10s
Best Surf 9AM (Sun 9th Aug)2.5ft (0.7m) 10s
Most Powerful 6PM (Tue 11th Aug)3ft (0.9m) 10s

Table - best surf conditions forecast for Rock Island over the next 16 days.


The Lowdown

Alright, let’s get into it. It’s Rusty here, and I’ve been staring at the charts for Rock Island for the next couple of weeks. Gotta be straight with you—this is a grim stretch for the most part. There’s a whole lot of nothing on the horizon, and I mean that in the most literal sense. The surf is tiny, and the energy is weak. We’re looking at a long, flat spell that’s going to test your patience.

The only real window of interest is way off, more than a week from now. We’re talking about the 22nd of August. Before that, it’s a whole lot of knee-high dribble. The water is sitting at a warm 81°, which is pretty much spot on for this time of year, so no surprises there. The vibe is warm, but the waves are not.

Now, about that gap. From now until the 22nd, there’s basically nothing worth getting wet for. We’ve got a few days where it’s surfable but super ordinary, but that’s a generous way of saying it. Most of the time, the swell is under 2ft, and the energy readings are in the low double digits—like 44, 32, 27. That’s weak, folks. The wind is often offshore, but when it’s blowing 18-25 mph, it’s just making the surface messy and hard to paddle into. Not a good look.

There’s a blip on Monday the 10th with a little more energy, but it’s still under 2ft. And while the wind is offshore and clean on Monday morning, the waves are just too small to get excited about. The period is around 10-11 seconds, which is okay, but there’s no power behind it.

So, we wait. The 22nd of August is the standout. I’m talking about Saturday afternoon. The swell jumps to 4ft from the south with a 12-second period. The energy reads 351, which is a solid, moderate push after all this nothing. But here’s the catch—it’s a reef break, and that S direction is right in its wheelhouse. The wind is gentle offshore, which means it should be clean and glassy. This is the one. This is the best we’re going to get. It’s still not massive, but compared to the rest of this forecast, it’s a proper wave.

Before that, on the morning of the 22nd, there’s a little pulse too, but it’s not as clean. And after that, the swell starts to fade again, with the wind turning onshore and messing things up by the 23rd and 24th.

So, to sum it up: don’t bother paddling out until the 22nd. That’s your window. It’s a long way off, so don’t book it in stone, but the long-range signals are there. Everything else is a bust. Keep the board in the car, but maybe keep the wax in the shade.

Stay patient, and stay stoked.

Rusty

Short Range Forecast

Moderate rain (total 15mm), heaviest on Tue night. Warm (max 29°C on Sun afternoon, min 23°C on Mon night). Wind will be generally light.

Days 4-6 Weather Summary

Heavy rain (total 32mm), heaviest during Wed night. Warm (max 30°C on Fri afternoon, min 24°C on Wed night). Winds increasing (light winds from the SE on Wed afternoon, fresh winds from the N by Thu morning).

Sunday
9
Monday
10
Tuesday
11
Wednesday
12
Thursday
13
Friday
14
Saturday
15
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
1
0
1
1
1
0
1
0
0
1
0
1
0
0
0
0
0
0
0
1
1
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.7
SSW
10
0.7
SSW
10
0.6
S
10
0.5
S
11
0.6
SSW
11
0.5
SSW
10
0.5
SSW
10
0.5
SSW
11
0.5
SSW
10
0.5
SSW
10
0.5
SSW
10
0.5
SSW
10
0.4
SSW
10
0.4
SSW
10
0.3
SSW
9
0.3
SSW
9
0.3
SSW
9
0.4
SSE
11
0.4
SSW
11
0.4
SSW
11
0.5
S
11
Wave Graph
Metric surfscale
Energy kJ
112
115
77
62
93
59
62
64
58
60
63
59
39
38
17
16
16
40
40
39
64
Wind (km/h)
5
SE
10
S
10
ENE
20
NE
10
NNE
20
NE
0
ENE
25
SSW
20
SSE
15
ENE
5
SE
20
NNE
35
N
25
NNE
25
NNE
30
NNE
20
NE
30
N
35
N
25
NNE
15
NE
Wind State
glassy
on
cross-off
off
off
cross-off
glassy
on
cross-on
cross-off
cross
off
off
off
off
off
off
cross-off
off
off
off
High Tide
4:09PM1.28m
00:45AM1.38m
4:47PM1.36m
2:03AM1.40m
5:17PM1.41m
3:09AM1.45m
5:43PM1.45m
4:05AM1.50m
6:08PM1.47m
4:55AM1.54m
6:31PM1.48m
5:41AM1.56m
6:55PM1.48m
Low Tide
7:53PM1.19m
8:54AM0.25m
9:16PM1.16m
9:46AM0.18m
10:08PM1.08m
10:31AM0.14m
10:48PM0.99m
11:12AM0.14m
11:25PM0.88m
11:48AM0.17m
00:00AM0.78m
12:23PM0.24m
00:35AM0.68m
part cloud
part cloud
thunderstorm
clear
part cloud
cloud
cloud
thunderstorm
rain showers
rain showers
clear
thunderstorm
thunderstorm
thunderstorm
thunderstorm
clear
thunderstorm
thunderstorm
thunderstorm
thunderstorm
thunderstorm
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:54
4:56
4:56
4:58
4:58
4:58
5:00
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:37
6:37
6:36
6:35
6:34
6:31
6:30
 mm
1
3
11
3
9
3
2
3
2
10
5
7
10
Temp °C
27
29
27
28
29
25
25
25
26
27
29
27
27
28
27
29
30
28
25
27
26
Feels °C
30
31
29
29
31
25
26
25
26
28
30
27
26
27
27
29
31
31
24
28
27
  • 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
How to use the Wavefinder 
submit an eyeball surf report

Quick surf report for Rock Island:

join our community of surf reporters

FREE! Surf-Forecast.com widget for your website

The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Rock Island surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.


Information about the Rock Island Surf forecast

The above surf forecast table for Rock Island provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Rock Island can be found by selecting the local surf guide option on the grey menu. Our Rock Island surf forecast is unique since it includes wave energy (power) that defines the real feel of the surf rather than just the height or the period. If you surf the same spot (Rock Island) regularly then make a mental note of the wave energy from the surf forecast table each time you go. Very soon you may start to choose your surf days based on the wave energy alone combined with our forecast of favourable offshore wind conditions. Our star ratings will help here and of course you will also find the usual wave height and period predictions on our surf forecasts as well as a full break down of the swell components under our advanced users option (to reveal that, click the little Einstein character under the tide times).

Further information to help with frequently asked questions about our surf forecast for Rock Island may be found under the help tab on the top menu and also by moving your mouse over the question marks on the surf forecast table itself. Please always bear in mind that the forecast is for near-shore open water and local factors at each surf break influence the actual breaking wave height, such as the beach / reef profile, water depths offshore and shelter.

Rock Island is 3 km (2 miles) from the city of Kamakura. If you plan a holiday in Kanagawa, look for hotels and other accommodation in Kamakura. Kamakura has rooms for a wide range of budgets as well as car hire and transport links.

Nearest locationNearest