Rock Island Surf Break

Lat Long: 35.29° N 139.55° E

Rock Island Surf Forecast and Surf Report

Issued: 2 am 23 Jul 2026 (local time)

Forecast update in  hr  min

Today's Rock Island sea temperature is
27.1° C
1.2° 

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 22 Jul 2026:

  • Best quality surf: Sunday 26 Jul, 9PM (local time) - 1ft (0.3m), 11s period, SE swell with cross-offshore winds.
  • Most powerful swell: Monday 27 Jul, 9PM (local time) - 3ft (0.9m), 6s period, SSW swell with 47 kJ wave energy.
  • Next surfable swell (1★+): Sunday 26 Jul, 9PM (local time) - 1ft (0.3m), 11s period with SE 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 (Jul 26) at 9PM. The primary swell is predicted to be 0.2m and 14s period with a secondary swell of 0.2m and 9s. Another secondary swell of 0.3m and 11s is also forecast. Another secondary swell of 0.6m and 4s is also forecast. The wind is predicted to be cross-offshore as the swell arrives.

The most powerful waves expected at Rock Island in the next 16 days are 0.9m 6s and forecast to arrive on Monday (Jul 27) at 9PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.4m 3s period and expected on Tuesday (Jul 28) at 3AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 9PM (Sun 26th Jul)1ft (0.3m) 11s
Best Surf 9PM (Sun 26th Jul)1ft (0.3m) 11s
Most Powerful 9PM (Mon 27th Jul)3ft (0.9m) 6s

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


The Lowdown

Alright, this is Rusty. Let's be straight with you – the next couple of weeks at Rock Island are looking pretty grim. There’s a big gap of nothing worth paddling out for right from the start. We're talking about a full ten days of flat, messy, or just plain poor conditions. The first time we see anything with a pulse is not until Monday, August 3rd, and even then it's only a flicker of hope.

For the first ten days, the swell is tiny, mostly under 2ft, and coming from the south or southeast. The wind is all over the shop, but often cross-on or onshore, which is just chopping up whatever ankle-biters are there. We get a few brief moments of glassy or offshore conditions, like Thursday morning, July 30th, but with a 0.7ft swell from the SSW, it's barely a ripple. The combined energy is weak, sitting in the low double digits (13 to 37) for most of that time. Nothing to get excited about.

Then, on Monday, August 3rd, things change. We finally see a pulse of energy. The swell bumps up to 3ft from the ESE, with a very long period of 18 seconds. The combined energy jumps to 445, which is a solid moderate push. The water temperature is 81°F, which is a touch warmer than normal for this time of year. However, the wind is onshore on the Monday morning, and it gets stronger in the afternoon. It's a tease. The morning of August 3rd is the only real standout, but it's described as "marginal" and the wind is wrong. It's a long-period groundswell, which for a reef break like Rock Island could actually be decent, but the onshore wind will ruin it. This one is for the experts only, as the swell is close to 3ft, but the period makes it powerful.

After that, it drops off again. The 4th has similar energy (320-294) but the wind is still onshore. By the 5th, the energy is gone. The 7th of August has a weird 3ft pulse from the SSW with a tiny 4-second period and glassy conditions, but it's a short-period windswell that won't have any shape. The afternoon sees the swell jump to 6ft from the SSW with a 6-second period, creating a combined energy of 243, but it's onshore and messy. That's a lot of white water and not much else.

Honestly, there's nothing here that's a "go" for a surf. The best bet is the morning of August 3rd, but it comes with a big caveat about the wind. If you're a patient local who knows the reef, you might find one or two, but for anyone else, it's a stay-at-home kind of fortnight.

Rusty.

Short Range Forecast

Moderate rain (total 10mm), heaviest on Sat night. Warm (max 32°C on Thu morning, min 25°C on Fri night). Wind will be generally light.

Days 4-6 Weather Summary

Moderate rain (total 13mm), heaviest on Sun night. Warm (max 29°C on Sun afternoon, min 23°C on Sun night). Wind will be generally light.

Thursday
23
Friday
24
Saturday
25
Sunday
26
Monday
27
Tuesday
28
Wednesday
29
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
0
0
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.4
SSW
6
0.4
SSW
6
0.2
SSE
10
0.2
SSE
9
0.2
SSE
9
0.3
SE
11
0.3
SE
10
0.3
SE
10
0.2
SSE
15
0.1
SE
15
0.3
SE
11
0.3
SE
11
0.3
SE
10
0.3
SE
10
0.6
S
6
0.3
SSW
9
0.3
SE
10
0.4
S
8
0.3
SSW
8
0.2
SSW
8
0.2
SSW
8
Wave Graph
Metric surfscale
Energy kJ
15
12
12
12
11
18
15
15
22
8
18
20
16
16
23
15
15
22
14
7
7
Wind (km/h)
10
ENE
20
S
10
ENE
5
E
20
SSW
10
S
15
NNE
15
S
10
ENE
10
S
15
SSW
20
NNE
15
NE
15
SSW
10
E
25
NNE
15
NE
10
NE
5
ESE
20
SSW
15
SSW
Wind State
cross-off
cross-on
cross-off
cross-off
on
cross-on
off
on
cross-off
cross-on
on
off
cross-off
on
cross-off
off
off
cross-off
glassy
on
on
High Tide
11:48AM1.12m
10:43PM1.38m
1:49PM1.13m
11:30PM1.38m
3:34PM1.21m
00:29AM1.39m
4:34PM1.30m
1:35AM1.40m
5:13PM1.37m
2:38AM1.44m
5:46PM1.42m
3:36AM1.48m
6:14PM1.45m
Low Tide
4:29PM0.91m
6:22AM0.44m
5:30PM1.04m
7:33AM0.35m
7:05PM1.13m
8:36AM0.25m
8:38PM1.16m
9:30AM0.16m
9:45PM1.13m
10:17AM0.10m
10:34PM1.08m
11:00AM0.06m
11:15PM1.00m
clear
clear
part cloud
part cloud
clear
part cloud
part cloud
rain showers
thunderstorm
clear
thunderstorm
thunderstorm
clear
part cloud
light rain
part cloud
rain showers
part cloud
part cloud
clear
clear
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:43
4:43
4:43
4:45
4:46
4:46
4:47
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:52
6:52
6:51
6:50
6:50
6:49
6:47
 mm
1
9
4
7
1
1
Temp °C
32
30
29
28
28
27
27
28
27
27
29
28
26
26
25
23
25
24
26
27
26
Feels °C
36
32
34
31
30
30
31
31
30
29
33
31
29
27
26
23
26
25
28
28
28
  • Map Icons:
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  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
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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.

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