Surf Forecasts:
Mainside surf forecast from 2 Sep 2026:
- Best quality surf: Sunday 6 Sep, 12AM (local time) - 5ft (1.5m), 10s period, N swell with cross-offshore winds.
- Most powerful swell: Wednesday 2 Sep, 6PM (local time) - 5ft (1.6m), 10s period, E swell with 500 kJ wave energy.
- Next surfable swell (1★+): Sunday 6 Sep, 12AM (local time) - 5ft (1.5m), 10s period with N swell.
Best Forecast Surf Conditions for Mainside this week:
The surf forecast for Mainside over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Sunday (Sep 06) at 12AM. The primary swell is predicted to be 1.5m and 10s period. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Mainside in the next 16 days are 1.6m 10s and forecast to arrive on Wednesday (Sep 02) at 6PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.6m 10s period and expected on Thursday (Sep 03) at 3AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Sun 6th Sep) | 5ft (1.5m) 10s |
| Best Surf | 12AM (Sun 6th Sep) | 5ft (1.5m) 10s |
| Most Powerful | 6PM (Wed 2nd Sep) | 5ft (1.6m) 10s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s take a look at what’s cooking for Mainside over the next couple of weeks.
Right off the bat, I’ve gotta be straight with you – the first few days are a bit of a write-off. We’ve got some swell around, but the wind is just messing it up. Wednesday morning the 2nd of September kicks off with a 5ft easterly swell and a light offshore wind, which sounds promising, but there’s a comment about *marginal* conditions. The water temp is sitting at 83°, which is bang on average for this time of year. The combined energy is moderate (382), but the quality just isn't there for a proper session. Wednesday afternoon and all of Thursday are blown out by cross-onshore winds and even a risk of thunderstorms, so don't bother.
Friday and Saturday are more of the same – messy, choppy, with poor conditions as the wind swings around. The swell drops a bit, and the energy fades. It’s a frustrating start.
Then, we finally get a window. Sunday the 6th of September is your best bet in the whole forecast. We’re looking at a clean 5ft swell from the north, with a light cross-offshore breeze. The combined energy is moderate (359 in the morning, 433 in the afternoon). The light breeze makes it look clean and workable. This is the standout. If you’ve got a board, that’s the morning to be out there.
After that, the wheels fall off again. Monday and Tuesday see the swell drop to under 3ft, with strong onshore winds. The energy plummets. The rest of the week into the second week is a mixture of strong winds, building swell, but it's all cross-onshore and messy. The swell gets big on the 10th of September – 8ft from the NNW – but with 25 mph winds, that’s just a washing machine. It’s kite-surfing territory, not for paddle surfing.
The 12th of September has a glimmer of hope with a 5ft northwesterly swell and offshore winds, giving a marginal call, but it’s not a standout. The week after that sees more strong winds and messy conditions, with a big spike in energy (1499) on the 17th of September, but again, it’s accompanied by 28 mph onshore winds. That’s messy and dangerous.
So, to sum it up: the only real window is Sunday the 6th. It’s a clean, fun-sized day. Everything else is a battle with the wind. Mainside is a consistent reef break, but this forecast is a tough one. Still, it only takes one good session to make it all worth it, and that Sunday is it.
Rusty.
Short Range ForecastHeavy rain (total 45mm), heaviest during Wed night. Warm (max 29°C on Wed morning, min 26°C on Wed afternoon). Winds decreasing (fresh winds from the NE on Wed night, light winds from the SW by Fri morning). | Days 4-6 Weather SummaryLight rain (total 3mm), mostly falling on Sun afternoon. Warm (max 29°C on Sun afternoon, min 27°C on Sat morning). Wind will be generally light. | ||||||||||||||||||||
Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | |||||||||||||||
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) | E 9 | E 9 | ESE 11 | E 10 | E 10 | E 10 | N 8 | N 7 | N 7 | N 9 | N 10 | N 10 | N 9 | N 10 | N 9 | N 8 | N 8 | N 9 | E 12 | E 10 | NNW 9 |
Wave Graph | |||||||||||||||||||||
364 | 332 | 0 | 392 | 284 | 121 | 169 | 108 | 79 | 347 | 440 | 400 | 348 | 414 | 257 | 76 | 54 | 109 | 137 | 125 | 243 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | cross-off | cross-off | cross-on | on | cross-on | cross-on | cross-on | on | cross | cross | cross-off | cross-off | cross-off | cross-off | cross | cross-on | cross | cross-on | cross-on | cross-on |
High Tide | 10:17AM1.97m | 10:08PM2.07m | 11:11AM1.79m | 10:46PM1.98m | 12:27PM1.61m | 11:36PM1.86m | 2:36PM1.53m | 1:00AM1.75m | 4:38PM1.63m | 3:05AM1.74m | 5:34PM1.77m | 4:36AM1.86m | 6:12PM1.90m | ||||||||
Low Tide | 4:07PM0.80m | 4:48AM0.46m | 4:45PM1.00m | 5:47AM0.54m | 5:33PM1.19m | 7:11AM0.62m | 7:06PM1.35m | 8:59AM0.62m | 9:37PM1.34m | 10:29AM0.52m | 11:02PM1.18m | 11:31AM0.41m | 11:53PM0.98m | ||||||||
6:07 | — | — | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | 6:11 | — | — | |
— | 6:47 | — | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — | — | 6:42 | — | |
mm | — | — | 17 | 6 | 4 | 4 | 4 | 4 | 6 | — | — | — | — | 2 | 1 | — | — | — | — | — | — |
Temp °C | 29 | 29 | 27 | 28 | 28 | 28 | 28 | 27 | 27 | 28 | 28 | 27 | 28 | 29 | 28 | 28 | 28 | 28 | 28 | 28 | 28 |
Feels °C | 29 | 28 | 28 | 31 | 30 | 32 | 32 | 29 | 31 | 30 | 29 | 30 | 32 | 33 | 32 | 30 | 29 | 30 | 29 | 30 | 30 |
Swell 1 Height (m) Direction Period (s) | SW 10 | SW 10 | ESE 11 | E 10 | E 10 | SW 11 | N 8 | N 7 | N 7 | N 9 | N 10 | N 10 | SSW 8 | SSW 8 | N 9 | N 8 | N 8 | N 9 | E 12 | E 10 | E 9 |
120 | 145 | 487 | 392 | 284 | 205 | 169 | 108 | 79 | 347 | 440 | 400 | 111 | 76 | 257 | 76 | 54 | 109 | 137 | 125 | 55 | |
Swell 2 Height (m) Direction Period (s) | E 13 | E 12 | SW 10 | NNE 6 | SW 12 | N 7 | SW 11 | SW 10 | SW 10 | SW 9 | SSW 9 | S 9 | E 9 | E 9 | SSW 8 | NW 6 | NW 6 | WNW 6 | WNW 6 | S 8 | E 11 |
13 | 12 | 120 | 75 | 228 | 56 | 258 | 163 | 130 | 99 | 147 | 74 | 7 | 15 | 46 | 33 | 31 | 25 | 26 | 10 | 92 | |
Swell 3 Height (m) Direction Period (s) | E 16 | — | — | SW 11 | N 7 | E 10 | E 9 | S 8 | S 9 | S 8 | E 10 | SW 9 | E 14 | E 13 | S 9 | SSW 8 | SSW 8 | SW 8 | SW 8 | SW 8 | S 8 |
5 | — | — | 187 | 56 | 121 | 42 | 92 | 108 | 68 | 17 | 50 | 4 | 4 | 42 | 53 | 36 | 15 | 10 | 10 | 4 | |
Wind waves Height (m) Direction Period (s) | E 9 | E 9 | NE 6 | — | — | SW 4 | — | — | — | — | NNW 3 | — | N 9 | N 10 | NW 5 | — | — | NNE 3 | N 8 | NNW 6 | NNW 9 |
364 | 332 | 100 | — | — | 24 | — | — | — | — | 1 | — | 348 | 414 | 13 | — | — | 1 | 80 | 75 | 243 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 14 | 1 | 621 | 24 | 15 | 29 | 15 | 29 | 24 | 9 | 39 | 0 | 0 | 0 | 0 | 39 | 39 | 39 | 764 | 36 | 36 |
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.











