Surf Forecasts:
Big Bay surf forecast from 18 Aug 2026:
- Best quality surf: Saturday 22 Aug, 8PM (local time) - 13ft (4.0m), 13s period, SW swell with cross-offshore winds.
- Most powerful swell: Saturday 22 Aug, 8PM (local time) - 13ft (4.0m), 13s period, SW swell with 5,746 kJ wave energy.
- Next surfable swell (1★+): Tuesday 18 Aug, 11AM (local time) - 8ft (2.4m), 12s period with WSW swell.
Best Forecast Surf Conditions for Big Bay this week:
The surf forecast for Big Bay over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Tuesday (Aug 18) at 11AM. The primary swell is predicted to be 2.4m and 12s period with a secondary swell of 1.5m and 12s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Big Bay in the next 16 days are 4.0m 13s and forecast to arrive on Saturday (Aug 22) at 8PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 5s period and expected on Tuesday (Aug 25) at 8AM.
| Wave Type | Time (SAST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11AM (Tue 18th Aug) | 8ft (2.4m) 12s |
| Best Surf | 8PM (Sat 22nd Aug) | 13ft (4.0m) 13s |
| Most Powerful | 8PM (Sat 22nd Aug) | 13ft (4.0m) 13s |
Table - best surf conditions forecast for Big Bay over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s talk about what’s coming up for Big Bay.
We’ve got a solid run of surf ahead, but it’s not for the faint of heart. The water is sitting at 55°, which is about 5° colder than usual for this time of year – that’s a serious bite, so make sure you’ve got a thick wetsuit and booties. The swell window is open to the southwest, and the energy coming through is strong, with values often in the thousands (2413 to over 5000), meaning there’s plenty of power in the water.
The first real standout is Thursday the 20th of August. The morning brings a clean 10ft SW swell with a 13-second period and light cross-offshore winds. The combined energy is a massive 3031 – that’s serious grunt. This is top-tier, expert-level stuff. The waves will be big, powerful, and well-shaped, but at this size, it’s strictly for experienced surfers. Crowds are often a factor here, so expect company if you’re paddling out.
Another cracker lands on Sunday the 30th of August. Both the morning and afternoon are glassy, with an 12ft SW swell, 13-14 second period, and no wind. The energy readings are huge (4529 and 3905). This is as clean as it gets for a big day. Again, experts only – this is not a beginner’s playground.
The week in between has plenty of surf, but it’s mixed. The 22nd of August (Saturday) is a write-off for paddle surfing due to onshore winds and a messy 13ft on the afternoon, which would be more interesting for kite surfing. The 25th of August (Tuesday) offers a very clean 8ft SW swell with a long 14-second period and offshore winds, but that long period at a beach break can make it a bit straight; still, a quality option for those who know the bank.
The 28th of August (Friday) and 29th of August (Saturday) see clean, solid 8-10ft SW swell, but the winds are up around 15-19 mph, so it’s going to be a bit of a battle. The energy is still high (over 4800), so there’s plenty of push, but it’s not as clean as the standouts.
The forecast starts with a recommendation on Tuesday the 18th of August, with a clean 8ft swell and cross-offshore winds, but the water is much colder than normal. The run continues through to the 2nd of September, but the last day (the 2nd) looks messy with heavy rain and strong onshore winds, so that’s one to skip.
Overall, the best windows are the 20th and the 30th – both offering big, clean, powerful swell for the crew who are ready for it. Stay warm, stay safe, and I’ll see you out there.
Rusty
Short Range ForecastMostly dry. Very mild (max 16°C on Tue afternoon, min 12°C on Tue night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 2mm), mostly falling on Sat morning. Very mild (max 17°C on Fri afternoon, min 11°C on Fri morning). Wind will be generally light. | ||||||||||||||||||||
Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | |||||||||||||||
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) | WSW 12 | SW 13 | SW 12 | SW 12 | SW 12 | SW 12 | SW 13 | SW 13 | SW 12 | SW 11 | SW 11 | WSW 11 | SW 10 | SW 12 | SW 13 | SW 12 | SW 11 | SW 12 | WSW 12 | WSW 11 | SW 13 |
Wave Graph  | |||||||||||||||||||||
 kJ | 1735 | 2345 | 2379 | 1866 | 1638 | 1591 | 3031 | 2497 | 1524 | 969 | 802 | 340 | 947 | 4657 | 4284 | 2402 | 1807 | 1372 | 559 | 370 | 1044 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | off | cross-off | cross | cross-off | cross-off | cross-off | off | cross | cross-on | cross | on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 6:48PM1.29m | 7:12AM1.10m | 7:29PM1.15m | 8:07AM0.99m | 8:32PM1.04m | 9:49AM0.92m | 10:25PM0.98m | 11:54AM0.96m | 00:06AM1.04m | 12:58PM1.07m | 1:01AM1.13m | 1:36PM1.19m | 1:40AM1.24m | ||||||||
Low Tide | 12:30PM0.38m | 1:08AM0.42m | 1:06PM0.51m | 1:55AM0.54m | 1:57PM0.63m | 3:19AM0.62m | 3:53PM0.70m | 5:32AM0.61m | 6:08PM0.66m | 6:46AM0.52m | 7:07PM0.56m | 7:27AM0.41m | 7:45PM0.45m | ||||||||
 | |  | | | | |  | | | | |  | | | | | | | | | |
 | 7:22 | — | — | 7:20 | — | — | 7:20 | — | — | 7:18 | — | — | 7:16 | — | — | 7:16 | — | — | 7:15 | — | — |
 | — | 6:17 | — | — | 6:19 | — | — | 6:19 | — | — | 6:20 | — | — | 6:21 | — | — | 6:21 | — | — | 6:22 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | 2 | — | — | — | — | — | — | — | — |
Temp °C | 15 | 16 | 13 | 14 | 16 | 14 | 15 | 16 | 13 | 15 | 17 | 13 | 15 | 16 | 15 | 13 | 15 | 13 | 14 | 17 | 13 |
Feels °C | 13 | 13 | 10 | 12 | 13 | 12 | 13 | 13 | 9 | 13 | 16 | 13 | 12 | 12 | 13 | 11 | 12 | 11 | 11 | 14 | 11 |
Swell 1 Height (m) Direction Period (s) | WSW 12 | SW 13 | SW 12 | SW 12 | SW 12 | SW 12 | SW 13 | SW 13 | SW 12 | SW 11 | SW 11 | WSW 11 | SW 10 | SW 12 | SW 13 | SW 12 | SW 11 | SW 12 | WSW 12 | WSW 11 | SW 13 |
| kJ | 1735 | 2345 | 2379 | 1866 | 1638 | 1591 | 3031 | 2497 | 1524 | 969 | 802 | 340 | 947 | 4657 | 4284 | 2402 | 1807 | 1372 | 559 | 370 | 1044 |
Swell 2 Height (m) Direction Period (s) | SW 12 | — | — | — | — | — | — | — | — | — | WSW 11 | SSW 10 | — | — | — | — | — | — | SSW 10 | SSW 9 | WSW 11 |
| kJ | 678 | — | — | — | — | — | — | — | — | — | 379 | 255 | — | — | — | — | — | — | 264 | 236 | 198 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | SW 15 | SW 16 |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 54 | 375 |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | NW 2 | — | — | — | — | — | — | — | S 3 | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | 2 | — | — | — | — | — | — | — | 8 | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 6 | 0 | 0 | 6 | 0 | 0 | 340 | 0 | 0 | 34 | 2 | 37 | 37 | 0 | 0 | 0 | 0 | 0 | 39 | 0 |
Best forecast wave conditions in Cape Town | |||||||||||||||||||||
Best forecast wave conditions in South Africa | |||||||||||||||||||||
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Information about the Big Bay Surf forecast
The above surf forecast table for Big Bay provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Big Bay can be found by selecting the local surf guide option on the grey menu. Our Big Bay 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 (Big Bay) 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 Big Bay 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.
Big Bay is 8 km (5 miles) from the very large city of Robben Island. If you plan a holiday in Cape Town, look for hotels and other accommodation in Robben Island. Robben Island has rooms for a wide range of budgets as well as cheap car hire and transport links.
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