Surf Forecasts:
Big Bay surf forecast from 18 Aug 2026:
- Best quality surf: Thursday 20 Aug, 8AM (local time) - 10ft (3.0m), 13s period, SW swell with cross-offshore winds.
- Most powerful swell: Sunday 23 Aug, 5AM (local time) - 10ft (3.0m), 13s period, SW swell with 3,318 kJ wave energy.
- Next surfable swell (1★+): Tuesday 18 Aug, 11PM (local time) - 10ft (3.0m), 12s period with SW 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 11PM. The primary swell is predicted to be 3.0m and 12s period. 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 3.0m 13s and forecast to arrive on Sunday (Aug 23) at 5AM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.4m 6s period and expected on Tuesday (Aug 25) at 11AM.
| Wave Type | Time (SAST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11PM (Tue 18th Aug) | 10ft (3.0m) 12s |
| Best Surf | 8AM (Thu 20th Aug) | 10ft (3.0m) 13s |
| Most Powerful | 5AM (Sun 23rd Aug) | 10ft (3.0m) 13s |
Table - best surf conditions forecast for Big Bay over the next 16 days.
The Lowdown
Alright, let’s switch to feet and knots.
The water’s sitting at 55°F, which is about 5°F colder than usual for this time of year – that’s a noticeable chill, so don’t skimp on the rubber. The action kicks off Tuesday, August 18th, with clean 8-foot swell from the WSW, around 12 seconds, and cross-off winds. The combined energy is 2413, so there’s plenty of grunt. This is for experienced surfers, and the afternoon bumps up to 8+ feet, so expert only after lunch. The morning is the call.
Wednesday the 19th holds similar – 8-foot SW swell, 12 seconds, light cross-off, combined energy 1866. Clean and big. Still for the experienced crew.
Thursday the 20th is the standout. Morning brings a solid 10-foot SW swell with a 13-second period, light cross-off breeze, and combined energy hits 3078. That’s serious power. Glassy, clean, and pumping. This is the best session of the first week. Afternoon the wind picks up a bit, so get out early.
Friday the 21st fades – 7-foot and 6-foot, but wind turns cross and cross-on, making it messy. Energy drops to 969 and 1245. Not worth it.
Saturday the 22nd is a dud. Rain showers, cross-on wind, and a tiny 3-foot swell in the morning. Afternoon jumps back to 10-foot but the wind is still cross-on, and the conditions are marginal. The morning is a waste.
Sunday the 23rd is back – 10-foot SW swell, 12 seconds, cross-off winds, combined energy 2329. Clean and powerful. Monday the 24th drops to 6 feet, still clean, energy down to 1014. A nice smaller day.
The real standout is Thursday the 20th morning. That’s the one to circle. Big, clean, powerful, perfect wind. After that, the next sweet spot is the morning of Wednesday the 26th – glassy conditions, 6-foot WSW swell, 12 seconds, 1083 combined energy. Dead calm wind, so it’ll be silky smooth. Not as big, but a beautiful session.
From the 27th into the 30th, there’s a mix. The 30th morning delivers a 8-foot SW swell with a very long 16-second period, combined energy of 3920. That’s a serious groundswell – best at a point or reef. Winds are light cross-shore, so it’s worth a look for experienced surfers.
The first week of September sees a 12-foot swell on the 1st, but with strong cross-on winds, it’s blown out. That’s more for kite surfers than paddle surfers.
Bottom line: Thursday the 20th morning is the best on offer. Clean, powerful, and solid. The crowd at Big Bay is often busy, so expect company. The break is fairly consistent, so you’ll get waves even on the smaller days, but when it’s this good, it’ll be worth the paddle.
Rusty out.
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 SummarySome drizzle, heaviest during Sat morning. Very mild (max 17°C on Fri afternoon, min 11°C on Sat 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 | SSW 10 | SW 11 | SW 14 | SW 12 | WSW 12 | SW 12 | WSW 12 | WSW 11 | SW 15 |
Wave Graph  | |||||||||||||||||||||
 kJ | 1735 | 2345 | 2379 | 1866 | 1638 | 1565 | 3078 | 2369 | 1513 | 969 | 866 | 366 | 229 | 1800 | 1991 | 2329 | 1888 | 1372 | 658 | 430 | 753 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | cross-on | 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 | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — | — | — |
Temp °C | 15 | 16 | 13 | 14 | 16 | 14 | 15 | 16 | 13 | 15 | 17 | 13 | 14 | 16 | 15 | 14 | 15 | 13 | 14 | 16 | 13 |
Feels °C | 13 | 13 | 10 | 12 | 12 | 12 | 13 | 13 | 10 | 13 | 16 | 13 | 12 | 13 | 14 | 12 | 12 | 10 | 12 | 13 | 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 | SSW 10 | SW 11 | SW 14 | SW 12 | WSW 12 | SW 12 | WSW 12 | WSW 11 | SW 15 |
| kJ | 1735 | 2345 | 2379 | 1866 | 1638 | 1565 | 3078 | 2369 | 1513 | 969 | 866 | 366 | 229 | 1800 | 1991 | 2329 | 1888 | 1372 | 658 | 430 | 753 |
Swell 2 Height (m) Direction Period (s) | SW 12 | — | — | — | — | — | — | — | — | — | WSW 11 | SSW 10 | WSW 6 | SW 17 | SW 10 | — | — | — | SSW 10 | SSW 10 | WSW 11 |
| kJ | 678 | — | — | — | — | — | — | — | — | — | 379 | 298 | 57 | 75 | 1082 | — | — | — | 356 | 226 | 245 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | WSW 11 | — | — | — | — | — | — | SW 14 | SW 9 |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | 143 | — | — | — | — | — | — | 70 | 170 |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | SSE 5 | — | — | N 4 | — | — | — | S 3 | — | — | S 4 | S 5 |
| kJ | — | — | — | — | — | — | — | — | — | 37 | — | — | 9 | — | — | — | 3 | — | — | 22 | 87 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 52 | 0 | 0 | 0 | 0 | 0 | 39 | 0 | 14 | 15 | 4 | 29 | 34 | 0 | 0 | 0 | 0 | 0 | 0 | 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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