
Surf Forecasts:
Mainside surf forecast from 5 Aug 2026:
- Best quality surf: Friday 7 Aug, 3AM (local time) - 13ft (4.0m), 17s period, E swell with cross-onshore winds.
- Most powerful swell: Friday 7 Aug, 3PM (local time) - 36ft (11.0m), 13s period, N swell with 42,979 kJ wave energy.
- Next surfable swell (1★+): Friday 7 Aug, 3AM (local time) - 13ft (4.0m), 17s period with E 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 (Aug 07) at 3AM. The primary swell is predicted to be 4.0m and 17s period with a secondary swell of 5.5m and 10s. The wind is predicted to be cross-onshore as the swell arrives.
The most powerful waves expected at Mainside in the next 16 days are 11.0m 13s and forecast to arrive on Friday (Aug 07) at 3PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 12.0m 14s period and expected on Saturday (Aug 08) at 12PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Fri 7th Aug) | 13ft (4.0m) 17s |
| Best Surf | 3AM (Fri 7th Aug) | 13ft (4.0m) 17s |
| Most Powerful | 3PM (Fri 7th Aug) | 36ft (11.0m) 13s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s break down the Mainside outlook in feet and miles per hour.
Right off the bat, I’ll be straight with you—this is not a classic run for this spot. The first real chance of a wave that’s worth paddling out for is Wednesday morning, August 5th. Before that, it’s flat or just plain messy. From Wednesday the 5th right through until the 12th, it’s a pretty bleak stretch, but we do get a tiny window of hope.
Wednesday morning, August 5th is your standout window, and honestly, it’s the only one worth getting excited about. Mainside is a consistent reef break, exposed to the north, and the optimum swell direction is from the north. We’ve got a long-period groundswell of 6 ft at 17 seconds from the east, which isn’t the ideal direction for the setup, but the energy is solid. The combined energy is pumping at 1682 (moderate wave energy). The water’s sitting at 87°, which is a touch warmer than normal for this time of year. The wind is a light 12 mph from the northeast, blowing cross-offshore, keeping things clean. For a more advanced crew, this is the one to look at. Crowds can pop up here sometimes, so you might have a few guys out, but it’s worth it for those clean, long-period lines.
Wednesday afternoon the wind picks up and swings more onshore, turning it lumpy. Forget it.
From Thursday the 6th through to Tuesday the 11th, it’s a write-off. We get a massive spike in swell on Friday the 7th—25 ft from the north with hurricane-force winds—but that’s a dangerous, violent mess. Do not even think about it. That swell is way too big for paddle surfing and the conditions are a straight-up hazard. After that, the wind stays brutal or the swell drops into the gutter.
There is a flicker on Wednesday morning, August 12th. Swell is small at 4 ft from the west with a short period of 8 seconds, but the wind is light at 6 mph from the south, blowing cross-offshore. The combined energy is only 205 (weak), but it’s clean. If you’re desperate for a session, this is a possibility, but it’s nothing to write home about. The rest of that week and into the next is tiny—knee-high dribble with onshore winds. Not worth your time.
So, the summary? Wednesday morning, August 5th is your best bet by a long shot. After that, sit tight because the second week is looking very quiet and uncertain. Forecasts can change, but right now, it’s a one-and-done kind of stretch.
Rusty.
Short Range ForecastHeavy rain (total 182mm), heaviest during Fri afternoon. Warm (max 30°C on Wed morning, min 28°C on Thu night). Winds increasing (light winds from the NE on Wed morning, extremely windy from the NNW by Fri afternoon). | Days 4-6 Weather SummaryHeavy rain (total 584mm), heaviest during Sat night. Warm (max 30°C on Sat morning, min 28°C on Sat morning). Winds decreasing (extremely windy from the SSE on Sat afternoon, fresh winds from the SSW by Mon night). | ||||||||||||||||||||
Wednesday 5 | Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | |||||||||||||||
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 17 | E 17 | E 17 | E 16 | E 16 | E 17 | N 12 | N 13 | NNW 11 | NW 14 | S 15 | ENE 10 | ENE 15 | E 14 | E 14 | W 14 | W 13 | W 12 | W 10 | W 9 | W 9 |
Wave Graph | |||||||||||||||||||||
1682 | 2149 | 3380 | 4804 | 5472 | 8480 | 14980 | 42979 | 3655 | 54 | 0 | 108 | 42 | 37 | 100 | 8253 | 4089 | 1921 | 563 | 332 | 288 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross | cross | cross | cross | cross-on | cross-on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | cross | cross | cross-off | cross | cross | cross |
High Tide | 11:26AM1.80m | 11:29PM1.96m | 12:40PM1.64m | 00:20AM1.89m | 2:33PM1.55m | 1:33AM1.83m | 4:33PM1.62m | 3:07AM1.83m | 5:46PM1.76m | 4:31AM1.92m | 6:33PM1.89m | 5:36AM2.05m | 7:10PM2.00m | ||||||||
Low Tide | 5:17PM0.88m | 6:17AM0.64m | 6:08PM1.08m | 7:37AM0.65m | 7:25PM1.25m | 9:12AM0.60m | 9:22PM1.33m | 10:37AM0.47m | 10:58PM1.26m | 11:41AM0.32m | 11:59PM1.13m | 12:31PM0.21m | 00:45AM0.97m | ||||||||
5:54 | — | — | 5:56 | — | — | 5:56 | — | — | 5:56 | — | — | 5:56 | — | — | 5:58 | — | — | 5:58 | — | — | |
— | 7:14 | — | — | 7:13 | — | — | 7:12 | — | — | 7:12 | — | — | 7:10 | — | — | 7:09 | — | — | 7:08 | — | |
mm | — | 1 | — | — | — | 10 | 43 | 116 | 12 | 56 | 91 | 256 | 107 | 48 | 18 | 4 | 2 | 2 | 1 | 1 | 2 |
Temp °C | 30 | 30 | 29 | 30 | 30 | 29 | 28 | 29 | 30 | 30 | 28 | 28 | 28 | 28 | 29 | 29 | 30 | 30 | 30 | 30 | 29 |
Feels °C | 31 | 31 | 30 | 28 | 26 | 23 | 15 | 23 | 33 | 24 | 10 | 10 | 11 | 14 | 20 | 23 | 28 | 30 | 32 | 32 | 33 |
Swell 1 Height (m) Direction Period (s) | E 17 | E 17 | E 17 | E 16 | E 16 | E 17 | ENE 17 | ENE 14 | NNW 11 | NW 14 | — | ENE 10 | E 15 | WSW 15 | WSW 15 | W 14 | W 13 | W 12 | W 10 | SW 11 | W 9 |
1682 | 2149 | 3380 | 4804 | 5472 | 8480 | 10089 | 4555 | 3655 | 54 | — | 108 | 17 | 6103 | 15497 | 8253 | 4089 | 1921 | 563 | 756 | 288 | |
Swell 2 Height (m) Direction Period (s) | S 8 | S 7 | — | — | — | — | — | — | NW 15 | — | — | ENE 15 | ENE 15 | E 14 | E 14 | E 14 | E 14 | E 13 | E 13 | W 9 | S 10 |
5 | 4 | — | — | — | — | — | — | 318 | — | — | 42 | 42 | 37 | 100 | 132 | 134 | 126 | 81 | 332 | 302 | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | N 16 | — | — | — | — | — | — | — | — | — | E 13 | E 12 | ENE 12 |
— | — | — | — | — | — | — | — | 245 | — | — | — | — | — | — | — | — | — | 199 | 75 | 49 | |
Wind waves Height (m) Direction Period (s) | NNE 6 | NNE 4 | NNE 6 | NNE 7 | NNE 8 | N 10 | N 12 | N 13 | S 9 | S 13 | S 15 | SSW 14 | SSW 14 | SW 14 | S 12 | SSW 12 | SSW 12 | SSW 12 | SSW 11 | S 11 | SW 11 |
22 | 34 | 111 | 653 | 1117 | 3966 | 14980 | 42979 | 3219 | 40988 | 60040 | 30562 | 28548 | 25900 | 4921 | 3811 | 3314 | 2850 | 1995 | 785 | 862 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 27 | 608 | 600 | 796 | 796 | 608 | 1330 | 1330 | 735 | 1296 | 735 | 735 | 735 | 735 | 622 | 622 | 618 | 600 | 600 | 600 | 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.











