Surf Forecasts:
Mainside surf forecast from 1 Sep 2026:
- Best quality surf: Saturday 5 Sep, 6AM (local time) - 4ft (1.2m), 9s period, N swell with cross-offshore winds.
- Most powerful swell: Tuesday 1 Sep, 9PM (local time) - 7ft (2.2m), 9s period, E swell with 854 kJ wave energy.
- Next surfable swell (1★+): Friday 4 Sep, 9AM (local time) - 3.5ft (1.1m), 8s 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 Friday (Sep 04) at 9AM. The primary swell is predicted to be 1.1m and 8s period. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Mainside in the next 16 days are 2.2m 9s and forecast to arrive on Tuesday (Sep 01) at 9PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 2.0m 9s period and expected on Wednesday (Sep 02) at 12AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9AM (Fri 4th Sep) | 3.5ft (1.1m) 8s |
| Best Surf | 6AM (Sat 5th Sep) | 4ft (1.2m) 9s |
| Most Powerful | 9PM (Tue 1st Sep) | 7ft (2.2m) 9s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright, Rusty here, let’s have a look at what’s cooking for Mainside.
Right off the bat, I gotta be straight with you – we’re looking at a pretty poor run of surf for the next couple of weeks. The first real window where you might want to paddle out doesn’t pop up until Saturday the 5th. Before that, conditions are just a mess with onshore winds and junk swell.
Let’s break it down. Tuesday and Wednesday have some chest-high swell around 6ft to 7ft from the East, but it’s either cross-off or battling a fresh breeze, making it pretty ordinary. Thursday is a write-off with onshore winds.
Then we get a little flicker of hope. Friday the 4th morning is all glassy, but with only 4ft from the North and a weak combined energy of 180, it’s really only just surfable. You'd be scratching for something to ride.
The standout in this whole spread is Saturday the 5th. We’ve got glassy conditions in the morning and light winds all day, with the swell coming from the North at 4ft to 4ft. The period ticks up to 9–10 seconds, and the combined energy sits in the moderate range (241–343). The wind is light enough that it should stay smooth. For a reef break that’s consistent and exposed to the north swell, this is about as good as it gets in this forecast. Keep in mind, Mainside can get a few bodies in the water sometimes, but the quality should outweigh the company.
After that, things fall apart again. From Sunday the 6th all the way through to Tuesday the 15th, it’s a solid stretch of poor conditions. Winds are all over the place – strong cross-shore, cross-onshore, and fresh breezes – with weak, short-period swell. There is a pulse of long-period energy from the East on the 9th, but the wind is just too rubbish.
Now, there’s a wild card way out at the end. Wednesday the 16th has a massive swell forecast, with the swell height jumping to 15ft in the morning and a ludicrous 23ft by afternoon. The combined energy is off the charts at 15014. The wind is cross-shore and fresh, so it’ll be lumpy, and for a reef break, a 23ft north swell is going to be a washing machine. This is strictly for the big-wave crew and only if you are absolutely on your game – it’s too big for anyone else.
Overall, the only session worth putting in the calendar is Saturday morning or afternoon. Otherwise, you might as well save the wax.
Stay safe out there.
Rusty
Short Range ForecastHeavy rain (total 21mm), heaviest during Thu afternoon. Warm (max 29°C on Wed morning, min 26°C on Wed night). Winds decreasing (fresh winds from the E on Tue night, light winds from the WNW by Thu night). | Days 4-6 Weather SummaryHeavy rain (total 32mm), heaviest during Sat afternoon. Warm (max 29°C on Sat morning, min 27°C on Fri night). Winds increasing (calm on Fri morning, fresh winds from the NE by Sun morning). | ||||||||||||||||||||
Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | |||||||||||||||
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 | E 14 | E 9 | E 9 | E 10 | E 11 | E 10 | N 7 | N 8 | NNE 8 | NNE 7 | N 9 | N 10 | N 10 | N 9 | N 9 | N 8 | N 8 | N 7 | N 9 |
Wave Graph | |||||||||||||||||||||
580 | 670 | 15 | 473 | 326 | 0 | 432 | 237 | 107 | 138 | 75 | 40 | 241 | 327 | 260 | 160 | 96 | 66 | 40 | 27 | 41 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | off | off | cross-off | cross | on | on | on | glassy | on | cross-on | glassy | cross-off | cross-off | cross-off | cross-off | cross | cross | cross-off | cross-off |
High Tide | 9:32AM2.11m | 9:36PM2.12m | 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 | ||||||||
Low Tide | 3:33PM0.63m | 4:00AM0.41m | 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 | ||||||||
6:07 | — | — | 6:07 | — | — | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | |
— | 6:49 | — | — | 6:47 | — | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — | |
mm | — | 2 | — | — | — | 1 | 4 | 11 | 3 | 1 | 2 | 3 | 1 | 7 | 7 | 9 | 2 | — | — | 3 | 1 |
Temp °C | 28 | 28 | 27 | 29 | 29 | 27 | 27 | 27 | 28 | 28 | 28 | 28 | 29 | 29 | 27 | 27 | 27 | 27 | 28 | 29 | 27 |
Feels °C | 27 | 27 | 26 | 28 | 29 | 26 | 30 | 30 | 32 | 34 | 33 | 33 | 34 | 33 | 28 | 27 | 27 | 29 | 31 | 33 | 30 |
Swell 1 Height (m) Direction Period (s) | SW 10 | SW 9 | SW 10 | SW 10 | SW 10 | E 10 | E 11 | SW 12 | SW 12 | SW 11 | SW 10 | SW 9 | N 9 | N 10 | N 10 | SSW 9 | SSW 9 | SSW 9 | SSW 9 | SSW 9 | S 9 |
33 | 30 | 61 | 120 | 170 | 541 | 432 | 303 | 433 | 328 | 160 | 144 | 241 | 327 | 260 | 151 | 137 | 144 | 188 | 137 | 73 | |
Swell 2 Height (m) Direction Period (s) | SSW 8 | S 8 | S 7 | E 13 | E 12 | SW 10 | SW 10 | E 10 | N 7 | N 8 | NNE 8 | S 10 | SSW 9 | SSW 9 | SSW 9 | N 9 | N 9 | N 8 | N 8 | N 7 | N 9 |
13 | 5 | 1 | 12 | 12 | 192 | 244 | 237 | 107 | 138 | 75 | 117 | 199 | 207 | 157 | 160 | 96 | 66 | 40 | 27 | 41 | |
Swell 3 Height (m) Direction Period (s) | E 15 | E 15 | E 14 | — | — | — | S 8 | N 6 | E 9 | E 9 | S 10 | NNE 7 | ESE 8 | E 10 | E 9 | E 9 | E 9 | E 9 | E 8 | E 8 | NW 6 |
4 | 5 | 15 | — | — | — | 5 | 51 | 85 | 42 | 125 | 40 | 12 | 16 | 15 | 15 | 14 | 14 | 12 | 12 | 5 | |
Wind waves Height (m) Direction Period (s) | E 9 | E 9 | E 9 | E 9 | E 9 | NE 5 | NNE 6 | W 3 | — | — | SSW 9 | — | — | SW 8 | — | SSE 8 | SSE 8 | ESE 3 | ESE 4 | E 3 | NE 4 |
580 | 670 | 721 | 473 | 326 | 40 | 60 | 4 | — | — | 360 | — | — | 138 | — | 53 | 67 | 6 | 10 | 6 | 14 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 735 | 608 | 608 | 600 | 1 | 39 | 24 | 15 | 15 | 0 | 24 | 27 | 0 | 0 | 1 | 13 | 770 | 1 | 10 | 10 | 10 |
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.











