Surf Forecasts:
Mainside surf forecast from 11 Aug 2026:
- Most powerful swell: Wednesday 12 Aug, 9AM (local time) - 1.5ft (0.4m), 11s period, ENE swell with 40 kJ wave energy.
Best Forecast Surf Conditions for Mainside this week:
The most powerful waves expected at Mainside in the next 16 days are 0.4m 11s and forecast to arrive on Wednesday (Aug 12) 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 0.9m 8s period and expected on Friday (Aug 14) at 12PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 9AM (Wed 12th Aug) | 1.5ft (0.4m) 11s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright, folks, Rusty here again. Let’s be honest with you – this 16-day forecast is a real bummer. We’re looking at our local spot, Mainside, and the charts are showing a whole lot of nothing. There’s no real swell on the horizon, and the little waves we see are just pathetic. It’s a long stretch of flatness, starting from the 12th of August and going all the way through to the 27th.
Now, let’s talk about the only break on offer, Mainside. It’s a consistent reef break, but it’s a bit of a tease. On the morning of the 12th, we’ve got a tiny 1ft wave from the ENE, with a long 11-second period and weak wave energy (40). The wind is a cross-offshore from the south, which keeps the surface clean, but honestly, for a paddle surfer, the swell is just too small to get excited about. The water temp is a normal 84° for this time of year.
The next few days are a repeat of the same story. Thursday the 13th and Friday the 14th offer some glassy conditions, especially on Thursday afternoon with a cross-off wind, but the swell is still a paltry 1ft to 2ft max. The wave energy is low, and the period is short, so there’s no power behind it.
Over the weekend, the 16th and 17th, we get a nice offshore breeze from the ESE at 12 mph, which will clean up the surface right up. But the swell is still stuck at 1.0ft, and the combined energy is just a weak 20-23. The 11th of August through the 21st is more of the same: tiny waves, but the wind does stay favorable for a clean surface.
The real kicker is that from the 22nd of August onwards, the wave heights drop to zero. We’re looking at completely flat, glassy conditions on the 23rd and 24th, with no swell at all. The wind is calm, but there’s nothing to ride. The 25th and 26th show a tiny 0.7ft wave from the east, but with a cross-shore wind that’s going to blow it out. It’s just not worth it.
The only standout, if you can call it that, is the period from the 16th to the 17th of August. The offshore wind is a major positive, and the surface will be clean. The swell is tiny, but if you’re desperate for a tiny, clean wave, that’s your best bet. For a powerful, rideable wave, this is a complete write-off. This setup is more interesting for a kite surfer to get a bit of a slide, but for a paddle surfer, you’re best off doing something else.
Rusty.
Short Range ForecastModerate rain (total 18mm), heaviest on Wed afternoon. Warm (max 29°C on Thu afternoon, min 26°C on Wed afternoon). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 29°C on Sat morning, min 27°C on Sat night). Wind will be generally light. | ||||||||||||||||||||
Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | |||||||||||||||
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) | ENE 11 | ENE 11 | N 8 | N 8 | N 7 | N 8 | N 7 | N 6 | W 6 | ENE 11 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | NE 10 | NE 10 |
Wave Graph  | |||||||||||||||||||||
 kJ | 40 | 23 | 22 | 28 | 24 | 20 | 15 | 7 | 6 | 23 | 23 | 20 | 20 | 20 | 20 | 19 | 19 | 19 | 20 | 27 | 26 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | off | glassy | glassy | glassy | cross-on | glassy | cross-off | cross-off | off | off | off | off | off | off | off | cross-off | cross-off | cross-off |
High Tide | 7:43PM2.07m | 7:14AM2.24m | 8:13PM2.13m | 7:57AM2.27m | 8:42PM2.15m | 8:37AM2.24m | 9:11PM2.15m | 9:15AM2.15m | 9:39PM2.13m | 9:54AM2.02m | 10:07PM2.08m | 10:34AM1.85m | 10:36PM2.01m | ||||||||
Low Tide | 1:14PM0.15m | 1:25AM0.82m | 1:52PM0.15m | 2:03AM0.69m | 2:27PM0.21m | 2:39AM0.60m | 3:00PM0.32m | 3:15AM0.54m | 3:31PM0.46m | 3:52AM0.54m | 4:00PM0.62m | 4:31AM0.58m | 4:28PM0.80m | ||||||||
 | |  | | |  |  | | | |  |  | | | | | | | | | | |
 | 5:58 | — | — | 5:58 | — | — | 6:00 | — | — | 6:00 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — |
 | — | 7:07 | — | — | 7:07 | — | — | 7:07 | — | — | 7:06 | — | — | 7:05 | — | — | 7:04 | — | — | 7:02 | — |
mm | 3 | 5 | 1 | 2 | 2 | 1 | — | 3 | 1 | — | — | — | — | — | — | — | — | — | — | — | 4 |
Temp °C | 27 | 26 | 27 | 28 | 29 | 28 | 28 | 28 | 28 | 29 | 29 | 27 | 29 | 29 | 27 | 28 | 29 | 27 | 29 | 29 | 27 |
Feels °C | 30 | 30 | 32 | 33 | 34 | 32 | 33 | 32 | 33 | 34 | 33 | 31 | 31 | 31 | 29 | 30 | 30 | 28 | 32 | 30 | 28 |
Swell 1 Height (m) Direction Period (s) | SW 9 | SW 9 | S 8 | S 9 | SW 8 | SW 8 | SW 9 | SSW 8 | SW 9 | SSW 8 | SSW 8 | SSW 9 | SSW 9 | SSW 9 | SSW 9 | SSW 9 | SSW 9 | SW 9 | SW 9 | SSW 8 | SSW 9 |
| kJ | 117 | 73 | 69 | 52 | 55 | 57 | 75 | 78 | 37 | 78 | 88 | 119 | 121 | 94 | 141 | 101 | 101 | 83 | 77 | 47 | 52 |
Swell 2 Height (m) Direction Period (s) | S 9 | S 9 | SW 9 | SW 8 | S 8 | S 8 | S 8 | N 6 | S 8 | ENE 11 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | E 5 | ENE 10 | ENE 10 | ENE 10 | NE 10 | NE 10 |
| kJ | 78 | 53 | 46 | 41 | 35 | 34 | 35 | 7 | 33 | 23 | 23 | 20 | 20 | 20 | 20 | 15 | 19 | 19 | 20 | 27 | 26 |
Swell 3 Height (m) Direction Period (s) | ENE 11 | ENE 11 | N 8 | N 8 | N 7 | N 8 | N 7 | W 6 | W 6 | NNW 4 | E 5 | W 6 | W 6 | S 9 | W 8 | ENE 10 | W 6 | W 6 | SE 10 | SE 10 | SE 10 |
| kJ | 40 | 23 | 22 | 28 | 24 | 20 | 15 | 7 | 6 | 2 | 5 | 3 | 3 | 13 | 10 | 19 | 3 | 3 | 4 | 4 | 4 |
Wind waves Height (m) Direction Period (s) | SSE 3 | — | ESE 6 | — | — | — | — | — | — | — | — | E 5 | E 5 | E 5 | ESE 5 | ESE 5 | ESE 4 | ESE 4 | ESE 5 | ESE 5 | E 5 |
| kJ | 4 | — | 12 | — | — | — | — | — | — | — | — | 13 | 21 | 21 | 28 | 32 | 10 | 25 | 22 | 15 | 27 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 14 | 10 | 10 | 10 | 10 | 10 | 10 | 36 | 10 | 10 | 10 | 10 | 14 | 14 | 14 | 14 | 14 | 14 | 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.
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