Surf Forecasts:
Mainside surf forecast from 14 Aug 2026:
- Best quality surf: Thursday 20 Aug, 12AM (local time) - 5ft (1.6m), 7s period, E swell with offshore winds.
- Most powerful swell: Thursday 20 Aug, 12AM (local time) - 5ft (1.6m), 7s period, E swell with 240 kJ wave energy.
- Next surfable swell (1★+): Wednesday 19 Aug, 6AM (local time) - 3ft (0.9m), 7s period with ENE 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 Wednesday (Aug 19) at 6AM. The primary swell is predicted to be 0.9m and 7s 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 7s and forecast to arrive on Thursday (Aug 20) at 12AM. Winds are predicted to be 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 Thursday (Aug 20) at 3PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Wed 19th Aug) | 3ft (0.9m) 7s |
| Best Surf | 12AM (Thu 20th Aug) | 5ft (1.6m) 7s |
| Most Powerful | 12AM (Thu 20th Aug) | 5ft (1.6m) 7s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
G’day, Rusty here. Got to level with you – the next two weeks at Mainside are a total bust. It’s a full 16-day stretch with no surf worth paddling out for. Flat spells and tiny, weak waves with rubbish conditions are all that’s on offer. The best you’ll see is a knee-high ankle-biter, and even that’s getting wrecked by wind.
First real chance isn’t until 14th August (Friday afternoon), but it’s barely a wobble. Swell is 0.3ft from the ENE with a short 10-second period and only 16 combined energy units. A light cross-onshore breeze is messing with it. Water is 83°F, about normal for this time of year, but you won’t be getting wet anyway.
Saturday the 15th morning has a 0.5ft ENE swell with 11-second period, and the wind flips offshore – clean but no push. Energy is a weak 23. That afternoon goes glassy with the same tiny swell – beautiful conditions, zero waves.
Sunday the 16th through Tuesday the 18th all show 0.5ft ENE swell with moderate offshore wind (ESE to E at 12-16 mph). Energy sticks between 18 and 23. It’s clean as anything, but you’d be bobbing on flat water. A complete flat spell hits Tuesday afternoon (18th) when swell and energy both disappear.
We get a short pulse on Wednesday the 19th: 2ft to 2ft from the east with a short 7-second period. The energy reaches 114 on the afternoon session – moderate – but wind is cross-offshore at 12-16 mph. Short period and cross-offshore wind means messy, lumpy waves. Not worth it. Thursday the 20th drops back to 0.8ft-1ft east swell, period still short at 7 seconds, energy falling to 41 and then 24.
After that, it’s tiny dribbles or nothing through to 29th August. There’s a half-decent 1ft east swell with a 12-second period on the 26th (Wednesday) morning and afternoon, energy reading 106 and 102 – solid moderate energy with some longer-period groundswell feel. Wind is onshore from the west at 9 mph. That longer-period swell doesn’t do much on a reef break, and with onshore wind, it’ll be bumpy and weak. The 27th has a 0.8ft east swell, 11-second period, energy in the 70s, but wind is cross at 16 mph from the southwest – choppy and ugly.
Bottom line: save your time. There’s nothing here worth dragging a board out for. Forecasts can change around here, but for now, it’s a dry spell.
Rusty.
Short Range ForecastSome drizzle, heaviest during Sun morning. Warm (max 29°C on Sat morning, min 27°C on Sat night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 16mm), heaviest on Tue night. Warm (max 29°C on Tue morning, min 27°C on Tue night). Mainly fresh winds. | ||||||||||||||||||||
Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | |||||||||||||||
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 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 9 | ENE 9 | E 7 | E 7 | E 7 | ESE 8 | SE 9 | ESE 9 | SSE 10 | S 10 | S 10 |
Wave Graph | |||||||||||||||||||||
23 | 23 | 20 | 20 | 20 | 19 | 20 | 19 | 19 | 18 | 17 | 8 | 63 | 100 | 240 | 0 | 0 | 0 | 0 | 0 | 0 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | off | off | off | off | off | off | off | off | cross-off | cross-off | cross-off | off | off | off | off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 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 | 12:19PM1.50m | 11:42PM1.80m | 2:15PM1.40m | 00:33AM1.69m | ||||||||
Low Tide | 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 | 6:04AM0.75m | 5:24PM1.15m | 7:13AM0.83m | 6:02PM1.32m | ||||||||
6:00 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | 6:03 | — | — | 6:03 | — | — | |
— | 7:06 | — | — | 7:05 | — | — | 7:04 | — | — | 7:02 | — | — | 7:01 | — | — | 7:00 | — | — | 7:00 | — | |
mm | — | — | — | 1 | — | — | — | — | — | — | — | 4 | 1 | — | 1 | 3 | 4 | 3 | 4 | 1 | 3 |
Temp °C | 29 | 29 | 27 | 28 | 28 | 27 | 28 | 29 | 27 | 29 | 29 | 27 | 29 | 29 | 28 | 28 | 28 | 27 | 28 | 28 | 27 |
Feels °C | 35 | 33 | 30 | 30 | 30 | 28 | 29 | 30 | 29 | 30 | 30 | 28 | 32 | 31 | 31 | 30 | 29 | 28 | 30 | 29 | 28 |
Swell 1 Height (m) Direction Period (s) | SW 8 | SSW 8 | SSW 8 | SW 8 | SW 8 | SW 9 | SW 9 | SW 9 | SW 9 | SSW 9 | SW 9 | SSW 9 | NNE 4 | NNE 5 | SSW 9 | S 9 | ESE 8 | ESE 9 | SSE 10 | ESE 8 | ESE 7 |
69 | 52 | 55 | 70 | 69 | 120 | 81 | 77 | 61 | 53 | 27 | 30 | 7 | 6 | 15 | 25 | 176 | 207 | 720 | 65 | 42 | |
Swell 2 Height (m) Direction Period (s) | S 9 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | SSW 8 | ENE 9 | SSW 9 | SSW 8 | SW 9 | SW 9 | S 9 | S 10 | SW 9 | SW 10 | SW 10 |
14 | 23 | 20 | 20 | 20 | 19 | 20 | 19 | 19 | 18 | 13 | 8 | 15 | 13 | 13 | 13 | 43 | 159 | 14 | 15 | 17 | |
Swell 3 Height (m) Direction Period (s) | ENE 11 | SSE 8 | W 6 | S 9 | W 7 | SE 11 | SE 11 | ESE 11 | SE 10 | SE 10 | ENE 9 | SSE 6 | SW 8 | SW 9 | SW 9 | — | SW 9 | SW 9 | — | ESE 11 | ESE 11 |
23 | 14 | 3 | 14 | 4 | 4 | 4 | 11 | 4 | 4 | 17 | 4 | 11 | 12 | 3 | — | 13 | 13 | — | 12 | 11 | |
Wind waves Height (m) Direction Period (s) | — | — | ESE 4 | ESE 5 | ESE 5 | ESE 4 | ESE 5 | ESE 6 | ESE 5 | ESE 6 | E 6 | ENE 6 | E 7 | E 7 | E 7 | ESE 8 | SE 9 | — | — | S 10 | S 10 |
— | — | 4 | 19 | 23 | 21 | 19 | 20 | 22 | 50 | 58 | 60 | 63 | 100 | 240 | 240 | 571 | — | — | 426 | 354 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 10 | 10 | 10 | 14 | 14 | 14 | 14 | 14 | 14 | 14 | 10 | 10 | 1 | 13 | 0 | 10 | 650 | 650 | 618 | 14 | 73 |
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.











