Surf Forecasts:
Mainside surf forecast from 12 Aug 2026:
- Most powerful swell: Wednesday 19 Aug, 3PM (local time) - 2.5ft (0.7m), 10s period, ENE swell with 81 kJ wave energy.
Best Forecast Surf Conditions for Mainside this week:
The most powerful waves expected at Mainside in the next 16 days are 0.7m 10s and forecast to arrive on Wednesday (Aug 19) at 3PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.5m 9s period and expected on Thursday (Aug 20) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 3PM (Wed 19th Aug) | 2.5ft (0.7m) 10s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
# Mainside Surf Outlook
Alright folks, let's have a look at what's on offer at Mainside over the next couple of weeks. Straight up, I gotta be honest with you – this stretch is looking pretty bleak. We're staring down the barrel of a 16-day window with nothing but poor surf conditions across the board. Every single morning and afternoon gets a score of zero, so there's no standout session to get excited about.
Starting from Thursday the 13th of August, we've got tiny swell hovering around 2 ft to 2 ft from the north and east-northeast, with short periods of 7 to 8 seconds. Wave energy is weak – sitting at 28 (combined energy) on Thursday morning – and the wind is all over the place, switching from east cross-off to north-northwest cross-on. The surf is clean-ish but just too small to do anything with. Friday and Saturday follow the same pattern: swell drops to 1.0 ft to 1 ft, periods short, and the wind keeps shifting around. We're looking at light cross-shore breezes and poor surf.
Now, Sunday the 16th through Monday the 17th brings a bit of a tease – we get some offshore winds from the southeast, 9 to 12 mph, which keeps things clean. But the swell is still only 1.0 ft from the east-northeast, period around 10 seconds, and energy is just 20. It's offshore and clean, but with barely a ripple to ride. Tuesday the 18th stays similar with cross-off winds and clean conditions, but again, tiny swell.
The first real flicker of hope comes on Thursday the 20th of August. The morning shows a bump to 3 ft from the east, period 9 seconds, and energy jumps to 106 – that's moderate wave energy. We've got fresh offshore winds from the southeast at 19 mph, so the surface will be clean. But by afternoon, the swell collapses back to 0.7 ft. It's a brief window, and with the offshore breeze, it might offer a few small, clean waves for the early birds. Still, 3 ft is pretty small, and the period is short, so don't expect much push.
From the 21st through the 23rd, we're back to ankle-biters – 0.3 ft to 0.7 ft, energy in the single digits, and the wind is all over the place. The 22nd of August afternoon goes glassy with zero wind, which is lovely, but with 0.7 ft swell, it's a flat calm. Not worth paddling out.
Then things get properly wild from the 24th of August onward. Winds ramp up to storm force, hitting 56 mph from the north-northeast on the 25th, creating a massive cross-chop. This is no longer a surf setup – with that kind of wind and the beach-and-reef layout, it's looking more interesting for kite surfing than paddle surfing. Swell tries to come back on the 26th and 27th with 2 ft to 3 ft from the east, period around 9 to 10 seconds, and energy peaks at 132 on the 27th morning. But the wind is gale force from the southwest, cross-onshore, and it's completely blown out. The 28th of August Friday morning sees a lull in wind to 34 mph from the south, cross-off, and clean conditions, but the swell is only 2 ft with energy at 48. Still poor.
Water temperature is about average for this time of year, nothing unusual to report.
Honestly, there's no standout session here. The best you could hope for is the morning of Thursday the 20th of August, with that 3 ft east swell, fresh offshore winds, and clean conditions – but it's marginal at best. The rest of the window is a write-off. When a spot has this many consistent poor ratings, it's just one of those blank runs. Forecasts can change, so keep an eye on it, but right now, I'd leave the board at home.
Rusty.
Short Range ForecastLight rain (total 2mm), mostly falling on Fri morning. Warm (max 29°C on Fri afternoon, min 27°C on Thu morning). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 5mm), mostly falling on Mon morning. Warm (max 29°C on Sun morning, min 26°C on Tue night). Wind will be generally light. | ||||||||||||||||||||
Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | |||||||||||||||
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) | N 8 | N 7 | N 7 | 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 | W 5 | E 6 | E 10 | ENE 10 | NNE 6 |
Wave Graph | |||||||||||||||||||||
28 | 15 | 8 | 16 | 7 | 7 | 23 | 23 | 20 | 20 | 20 | 20 | 20 | 19 | 19 | 18 | 1 | 22 | 49 | 81 | 16 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | cross-on | glassy | cross-off | on | cross | glassy | cross-on | cross-off | off | off | off | off | off | off | cross-off | off | cross-off | cross-off | cross-off | off |
High Tide | 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 | 11:19AM1.67m | 11:07PM1.91m | ||||||||
Low Tide | 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 | 5:13AM0.66m | 4:55PM0.98m | ||||||||
5:58 | — | — | 6:00 | — | — | 6:00 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | |
— | 7:07 | — | — | 7:07 | — | — | 7:06 | — | — | 7:05 | — | — | 7:04 | — | — | 7:02 | — | — | 7:01 | — | |
mm | — | — | — | 1 | — | 1 | — | — | — | — | — | 1 | 2 | 2 | — | — | — | — | — | — | 1 |
Temp °C | 28 | 28 | 28 | 28 | 29 | 27 | 28 | 29 | 28 | 29 | 29 | 27 | 28 | 28 | 27 | 28 | 28 | 27 | 29 | 29 | 28 |
Feels °C | 33 | 32 | 33 | 32 | 33 | 30 | 34 | 33 | 33 | 32 | 32 | 30 | 31 | 29 | 29 | 28 | 29 | 28 | 32 | 31 | 29 |
Swell 1 Height (m) Direction Period (s) | SW 8 | SW 8 | SW 9 | SSW 8 | SW 8 | SW 9 | SW 8 | SW 8 | SSW 9 | SSW 8 | SSW 8 | SSW 9 | SSW 9 | SSW 9 | SW 9 | SW 9 | SSW 9 | E 6 | E 10 | S 8 | NNE 6 |
66 | 84 | 59 | 103 | 54 | 50 | 42 | 62 | 116 | 92 | 92 | 141 | 99 | 106 | 83 | 81 | 68 | 22 | 49 | 19 | 16 | |
Swell 2 Height (m) Direction Period (s) | S 9 | S 8 | S 8 | N 7 | S 9 | S 8 | S 8 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | SE 10 | SSW 9 | SW 9 | SW 9 | ESE 9 |
53 | 33 | 20 | 16 | 38 | 22 | 35 | 23 | 20 | 20 | 20 | 20 | 20 | 19 | 19 | 18 | 4 | 52 | 28 | 21 | 28 | |
Swell 3 Height (m) Direction Period (s) | N 8 | N 7 | N 7 | ENE 10 | N 6 | W 6 | ENE 11 | SSE 8 | W 6 | E 5 | SE 11 | SE 11 | SE 11 | SE 10 | SE 10 | ESE 10 | W 5 | ENE 10 | SSW 8 | ESE 10 | SSW 9 |
28 | 15 | 8 | 10 | 7 | 7 | 23 | 7 | 2 | 2 | 5 | 5 | 4 | 4 | 4 | 11 | 1 | 19 | 14 | 19 | 26 | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | ESE 4 | — | ESE 5 | ESE 5 | ESE 5 | ESE 5 | ESE 5 | ESE 5 | E 5 | — | — | ENE 10 | ESE 5 |
— | — | — | — | — | — | — | — | 2 | — | 5 | 15 | 37 | 31 | 30 | 23 | 42 | — | — | 81 | 36 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 10 | 29 | 10 | 10 | 36 | 10 | 10 | 10 | 10 | 10 | 14 | 14 | 14 | 14 | 14 | 10 | 14 | 10 | 10 | 1 | 621 |
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.











