Surf Forecasts:
Mainside surf forecast from 19 Aug 2026:
- Most powerful swell: Tuesday 25 Aug, 9AM (local time) - 6.5ft (2.0m), 16s period, E swell with 2,183 kJ wave energy.
Best Forecast Surf Conditions for Mainside this week:
The most powerful waves expected at Mainside in the next 16 days are 2.0m 16s and forecast to arrive on Tuesday (Aug 25) at 9AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 3.0m 10s period and expected on Saturday (Aug 22) at 12AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 9AM (Tue 25th Aug) | 6.5ft (2.0m) 16s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let's have a look at what's on the table for the next couple of weeks.
Honestly, this is a tough one. The forecast is pretty grim for the foreseeable future. We’ve got a solid stretch of poor surf conditions ahead, with strong offshore winds making it almost impossible to paddle into anything, and when there is a tiny bit of swell, it’s often accompanied by storm risks. The water temp is sitting right around average for this time of year at 84°F, so nothing unusual there.
The first real sniff of something rideable doesn't come until Tuesday the 25th of August. That morning, Mainside (a reef break for advanced surfers) could see a 7ft easterly groundswell with a very long 16-second period. The energy is strong at 2183, so there's some serious power behind it. Conditions are clean with a cross-offshore breeze, which sounds promising. But come afternoon, the wind swings cross-shore and the quality drops off a cliff. That Tuesday morning window is the only real standout in the whole 16-day forecast – it's the best on offer, but it's a narrow window. After that, we’re back into small, messy, or onshore conditions for the rest of the run.
There are long gaps of nothing but poor surf in between. The period from now right through to the 25th is a write-off, and after that Tuesday morning, it’s a slow slide back into marginal, small, and choppy waves. A few mornings around the 28th of August to the 1st of September show tiny, knee-high waves with clean offshore winds, but the energy is weak (under 100) and the swell is short-period. Not worth paddling out for unless you’re desperate for a float.
To be brutally honest, the only day that gets a thumbs up is the morning of Tuesday the 25th of August at Mainside. The rest of the 16 days is a struggle. If you’ve got a kite, the strong winds and lumpy conditions might be more your thing, but for a surfboard, it’s a waiting game.
Rusty.
Short Range ForecastHeavy rain (total 23mm), heaviest during Fri morning. Warm (max 29°C on Thu morning, min 26°C on Fri night). Winds increasing (moderate winds from the ESE on Thu afternoon, gales from the SE by Fri afternoon). | Days 4-6 Weather SummaryModerate rain (total 10mm), heaviest on Sun morning. Warm (max 29°C on Tue morning, min 27°C on Sun morning). Winds decreasing (strong winds from the ESE on Sun morning, moderate winds from the N by Tue night). | ||||||||||||||||||||
Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | |||||||||||||||
AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | |
Swell Height Map | |||||||||||||||||||||
Wave Height (m) Direction Period (s) | ESE 8 | ESE 7 | ESE 6 | ENE 8 | SE 7 | SE 10 | SE 10 | E 14 | SE 9 | S 10 | SSE 10 | SSE 10 | E 13 | ESE 18 | ESE 17 | E 16 | E 15 | E 14 | E 14 | ENE 14 | ENE 13 |
Wave Graph | |||||||||||||||||||||
0 | 0 | 0 | 13 | 0 | 0 | 0 | 4 | 0 | 0 | 0 | 0 | 3 | 0 | 0 | 2183 | 2069 | 1045 | 545 | 433 | 198 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | off | off | off | off | off | off | off | off | off | off | off | off | off | off | cross-off | cross | cross-on | on | on | on |
High Tide | 12:19PM1.50m | 11:42PM1.80m | 2:15PM1.40m | 00:33AM1.69m | 5:17PM1.48m | 2:15AM1.61m | 6:02PM1.61m | 4:01AM1.63m | 6:26PM1.73m | 5:05AM1.73m | 6:47PM1.83m | 5:50AM1.85m | 7:07PM1.92m | ||||||||
Low Tide | 5:24PM1.15m | 7:13AM0.83m | 6:02PM1.32m | 8:53AM0.84m | 8:41PM1.43m | 10:25AM0.77m | 11:03PM1.37m | 11:21AM0.66m | 11:53PM1.25m | 12:00PM0.54m | 00:24AM1.12m | 12:33PM0.45m | 00:51AM0.99m | ||||||||
6:03 | — | — | 6:03 | — | — | 6:03 | — | — | 6:03 | — | — | 6:03 | — | — | 6:05 | — | — | 6:05 | — | — | |
— | 7:00 | — | — | 7:00 | — | — | 7:00 | — | — | 6:59 | — | — | 6:58 | — | — | 6:57 | — | — | 6:55 | — | |
mm | — | 1 | 2 | 2 | 2 | 5 | 3 | 2 | 6 | 5 | 1 | 3 | — | 1 | — | — | — | — | — | — | 7 |
Temp °C | 29 | 28 | 27 | 27 | 27 | 27 | 28 | 27 | 27 | 27 | 28 | 27 | 27 | 27 | 28 | 29 | 28 | 27 | 28 | 28 | 28 |
Feels °C | 30 | 30 | 27 | 26 | 23 | 23 | 25 | 25 | 25 | 25 | 26 | 27 | 27 | 27 | 29 | 31 | 29 | 29 | 29 | 28 | 29 |
Swell 1 Height (m) Direction Period (s) | S 10 | S 9 | S 9 | S 9 | SW 9 | SW 10 | SW 10 | SW 10 | SW 10 | S 10 | SSE 10 | SSE 10 | ESE 16 | ESE 18 | ESE 17 | E 16 | E 15 | E 14 | E 14 | ENE 14 | ENE 13 |
44 | 78 | 76 | 54 | 93 | 60 | 117 | 124 | 96 | 449 | 721 | 335 | 619 | 1136 | 2024 | 2183 | 2069 | 1045 | 545 | 433 | 198 | |
Swell 2 Height (m) Direction Period (s) | SW 9 | SW 9 | SW 9 | SW 8 | — | — | — | E 14 | — | SW 10 | SW 10 | SW 9 | SSW 10 | SSW 10 | SSW 10 | SE 8 | SSW 10 | S 10 | SSW 9 | S 10 | S 10 |
12 | 13 | 13 | 45 | — | — | — | 4 | — | 60 | 46 | 43 | 61 | 64 | 83 | 69 | 205 | 90 | 126 | 90 | 90 | |
Swell 3 Height (m) Direction Period (s) | — | SW 9 | — | ENE 8 | — | — | — | — | — | ESE 15 | SE 16 | ESE 14 | E 13 | — | SSW 10 | S 10 | — | SW 10 | SE 10 | SW 9 | SW 9 |
— | 12 | — | 13 | — | — | — | — | — | 21 | 66 | 81 | 3 | — | 85 | 70 | — | 96 | 16 | 31 | 31 | |
Wind waves Height (m) Direction Period (s) | ESE 8 | ESE 7 | ESE 6 | SE 7 | SE 7 | SE 10 | SE 10 | SE 9 | SE 9 | ESE 6 | ESE 6 | ESE 6 | SE 9 | ESE 9 | ESE 9 | NE 4 | ENE 6 | NNE 5 | N 5 | N 5 | NNW 6 |
146 | 127 | 134 | 295 | 312 | 1540 | 1337 | 899 | 621 | 206 | 119 | 130 | 586 | 721 | 565 | 24 | 65 | 30 | 24 | 27 | 42 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 14 | 14 | 608 | 608 | 600 | 600 | 618 | 618 | 600 | 608 | 608 | 608 | 765 | 608 | 608 | 10 | 27 | 39 | 36 | 608 | 24 |
Best forecast wave conditions in Okinawa | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
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Information about the Mainside Surf forecast
The above surf forecast table for Mainside provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Mainside can be found by selecting the local surf guide option on the grey menu. Our Mainside 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 (Mainside) 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 Mainside 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.
Mainside is 11 km (7 miles) from the city of Ishikawa. If you plan a holiday in Okinawa, look for hotels and other accommodation in Ishikawa. Ishikawa has rooms for a wide range of budgets as well as car hire and transport links.











