
Surf Forecasts:
Big Bay surf forecast from 15 Sep 2026:
- Best quality surf: Thursday 17 Sep, 2AM (local time) - 8ft (2.5m), 13s period, SSW swell with offshore winds.
- Most powerful swell: Wednesday 16 Sep, 5AM (local time) - 10ft (3.0m), 14s period, WSW swell with 3,562 kJ wave energy.
- Next surfable swell (1★+): Thursday 17 Sep, 2AM (local time) - 8ft (2.5m), 13s period with SSW 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 Thursday (Sep 17) at 2AM. The primary swell is predicted to be 2.5m and 13s period with a secondary swell of 1.2m and 12s. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Big Bay in the next 16 days are 3.0m 14s and forecast to arrive on Wednesday (Sep 16) at 5AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.8m 6s period and expected on Sunday (Sep 20) at 8AM.
| Wave Type | Time (SAST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2AM (Thu 17th Sep) | 8ft (2.5m) 13s |
| Best Surf | 2AM (Thu 17th Sep) | 8ft (2.5m) 13s |
| Most Powerful | 5AM (Wed 16th Sep) | 10ft (3.0m) 14s |
Table - best surf conditions forecast for Big Bay over the next 16 days.
The Lowdown
Alright, let’s get into it. The outlook for Big Bay is a bit of a mixed bag, but there are a few windows that could be worth paddling out for. The forecast kicks off on Tuesday the 15th, but honestly, you’ll want to sit that one out. The day opens with a messy, lumpy 6 ft NW windswell with a short period of 6 seconds, and that cross-on 22 mph breeze just chops it to bits. Afternoon doesn’t improve – a 4 ft SW groundswell shows up, but the 25 mph cross-on wind is nasty. No surf to get excited about here.
Wednesday the 16th is where we start to see a glimmer of hope. The morning brings a cleaner picture with 6 ft of SW groundswell at 13 seconds and a fresh cross-off breeze at 22 mph. It’s still a bit rough around the edges for quality, but it’s a step up. The afternoon is similar with 6 ft, though still marginal. Thursday looks okay, with a solid 7 ft SW swell at 12 seconds and clean conditions from a cross-off wind, but the scores are middling. The real standout comes on Friday the 18th: that morning has offshore 19 mph winds, a 6 ft SW groundswell (moderate energy), and the wave comment gets a “fresh offshore and clean”. The afternoon keeps that 6 ft swell but with a longer 13-second period and still offshore. This is the best of the first week – clean, lined-up, and surfable for intermediates.
Saturday the 19th drops a bit in size (5 ft to 5 ft) but stays clean, and Sunday the 20th bumps back up to 6 ft of SW swell with good period (14 seconds) and clean cross-off breezes. Monday the 21st is a solid shout too: morning sees 6 ft WSWSW with gentle cross-off winds, and the wave report says “expect very good surf conditions” with moderate energy. That’s a prime window for a long session.
As we push into the second week, confidence drops a little, but there’s still fun to be had. Tuesday the 22nd has light offshore breeze (6 mph) and a clean 4 ft WSWSW groundswell – small but playful. Wednesday the 23rd is tiny (2 ft to 3 ft), so you might want to skip it unless you’re on a longboard. Things get tricky around Thursday the 24th with a 5 ft cross-on mess, and Friday the 25th afternoon looks interesting: a 7 ft SW swell at 14 seconds with a light cross-on breeze – that’s expert territory if you can handle the size (strong energy). Saturday the 26th is a standout in this later period: morning brings 7 ft of SW groundswell (14 seconds, strong energy) with a clean cross-off wind. This one has real power, so it’s for the experienced crew.
Monday the 28th morning is also worth a look – 7 ft S swell at 10 seconds, clean cross-off, and the wave comment says “excellent surf conditions for experienced surfers” – it’s a solid option for those who want a punchy, fast wave. The last gem is Tuesday the 29th morning: 5 ft SW groundswell with an exceptionally long 16-second period (very very long), gentle cross-off wind, and again “excellent surf conditions for experienced surfers”. That combination of long period and offshore wind will produce smooth, powerful lines at the point breaks and reefs.
Water temp at Big Bay kicks off at 55°F, which is about 5°F colder than the norm for this time of year – that’s well outside the usual range and feels notably cold. You’ll need a thick wetsuit for sure.
Overall, the pick of the entire forecast is Friday the 18th and Saturday the 26th and Tuesday the 29th. The first one is clean, moderate-sized, and offshore – a real session for the taking. The latter two are powerful groundswells with proper energy, but definitely for the experts. Crowds? The guidance says Big Bay gets crowded “often”, so expect company, especially on those standout days.
Rusty.
Short Range ForecastModerate rain (total 12mm), heaviest on Tue night. Very mild (max 17°C on Tue morning, min 12°C on Wed night). Winds decreasing (strong winds from the NNW on Tue afternoon, light winds from the SE by Wed night). | Days 4-6 Weather SummaryMostly dry. Very mild (max 19°C on Fri afternoon, min 13°C on Fri morning). Winds decreasing (fresh winds from the SSE on Sat night, light winds from the SE by Sun night). | ||||||||||||||||||||
Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | Saturday 19 | Sunday 20 | Monday 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) | NW 6 | SW 16 | SW 14 | WSW 13 | WSW 13 | SSW 13 | SW 12 | SW 12 | SW 11 | SW 11 | SW 13 | SW 13 | SW 12 | SW 12 | SW 13 | SW 14 | SW 14 | WSW 13 | WSW 12 | WSW 12 | WSW 11 |
Wave Graph | |||||||||||||||||||||
217 | 813 | 3430 | 983 | 1193 | 2049 | 1293 | 929 | 673 | 701 | 976 | 851 | 514 | 667 | 846 | 1330 | 1428 | 1066 | 769 | 565 | 366 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-off | cross-off | cross-off | off | cross-off | cross-off | cross-off | off | off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off |
High Tide | 5:29PM1.40m | 5:49AM1.24m | 6:00PM1.27m | 6:24AM1.13m | 6:36PM1.13m | 7:10AM1.01m | 7:30PM1.00m | 8:48AM0.92m | 9:37PM0.93m | 11:20AM0.96m | 11:39PM0.99m | 12:26PM1.08m | 00:34AM1.10m | ||||||||
Low Tide | 11:18AM0.26m | 11:44PM0.28m | 11:48AM0.38m | 00:15AM0.41m | 12:20PM0.51m | 00:53AM0.53m | 1:03PM0.63m | 2:02AM0.64m | 2:56PM0.73m | 4:47AM0.65m | 5:47PM0.67m | 6:11AM0.55m | 6:42PM0.56m | ||||||||
6:46 | — | — | 6:43 | — | — | 6:43 | — | — | 6:41 | — | — | 6:39 | — | — | 6:39 | — | — | 6:37 | — | — | |
— | 6:37 | — | — | 6:37 | — | — | 6:37 | — | — | 6:38 | — | — | 6:39 | — | — | 6:39 | — | — | 6:40 | — | |
mm | — | — | 12 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 17 | 16 | 14 | 15 | 16 | 14 | 15 | 17 | 15 | 16 | 19 | 16 | 18 | 19 | 16 | 17 | 18 | 15 | 18 | 20 | 16 |
Feels °C | 10 | 8 | 9 | 7 | 7 | 6 | 8 | 9 | 8 | 9 | 13 | 10 | 15 | 15 | 11 | 12 | 13 | 12 | 15 | 16 | 14 |
Swell 1 Height (m) Direction Period (s) | SW 11 | SW 16 | SW 14 | WSW 13 | WSW 13 | SSW 13 | SW 12 | SW 12 | SW 11 | SW 11 | SW 13 | SW 13 | SW 12 | SW 12 | SW 13 | SW 14 | SW 14 | WSW 13 | WSW 12 | WSW 12 | WSW 11 |
168 | 813 | 3430 | 983 | 1193 | 2049 | 1293 | 929 | 673 | 701 | 976 | 851 | 514 | 667 | 846 | 1330 | 1428 | 1066 | 769 | 565 | 366 | |
Swell 2 Height (m) Direction Period (s) | SW 18 | — | WNW 7 | SW 14 | SW 13 | W 12 | — | — | — | SW 14 | SW 18 | SW 16 | SW 15 | — | — | — | — | — | — | — | WSW 13 |
152 | — | 164 | 596 | 767 | 446 | — | — | — | 245 | 12 | 66 | 217 | — | — | — | — | — | — | — | 35 | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | W 20 | — | — | — | — | — | — | — | — | — | — | — |
— | — | — | — | — | — | — | — | — | 7 | — | — | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | NW 6 | NW 7 | — | SW 9 | S 6 | — | S 7 | S 6 | SSE 6 | SSE 6 | SSE 6 | SSE 6 | SSE 6 | SSE 6 | SSE 6 | S 6 | S 6 | S 5 | SSE 5 | S 4 | S 4 |
217 | 539 | — | 798 | 158 | — | 250 | 328 | 212 | 127 | 269 | 131 | 172 | 271 | 248 | 235 | 166 | 59 | 19 | 15 | 32 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 274 | 192 | 129 | 322 | 163 | 0 | 58 | 166 | 58 | 1286 | 1286 | 0 | 0 | 361 | 91 | 91 | 340 | 0 | 0 | 455 | 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.










