
Surf Forecasts:
Big Bay surf forecast from 12 Sep 2026:
- Best quality surf: Saturday 12 Sep, 8PM (local time) - 8ft (2.4m), 16s period, SW swell with offshore winds.
- Most powerful swell: Tuesday 15 Sep, 11PM (local time) - 10ft (3.0m), 15s period, WSW swell with 3,796 kJ wave energy.
- Next surfable swell (1★+): Saturday 12 Sep, 8PM (local time) - 8ft (2.4m), 16s 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 Saturday (Sep 12) at 8PM. The primary swell is predicted to be 2.4m and 16s period with a secondary swell of 1.5m and 8s. 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 15s and forecast to arrive on Tuesday (Sep 15) at 11PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.7m 6s period and expected on Friday (Sep 18) at 2PM.
| Wave Type | Time (SAST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8PM (Sat 12th Sep) | 8ft (2.4m) 16s |
| Best Surf | 8PM (Sat 12th Sep) | 8ft (2.4m) 16s |
| Most Powerful | 11PM (Tue 15th Sep) | 10ft (3.0m) 15s |
Table - best surf conditions forecast for Big Bay over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s have a look at what’s ahead for Big Bay.
We’ve got a solid run of SW groundswell on the charts starting this weekend, and for the most part, it’s a setup that’s going to favour experienced surfers. The water’s sitting at 56°F, which is much colder than normal for this time of year, so you’ll want the thickest rubber you’ve got if you’re paddling out at Big Bay.
This Saturday morning kicks things off with a 6ft SW swell at 14 seconds, and a moderate cross-off breeze. The combined energy is strong (1773), so there’s plenty of push. It’s a little on the messy side with that wind, but it’s surfable. Saturday afternoon picks up: 8ft SW at 16 seconds, a fresh offshore wind, and the energy jumps to 3383 – that’s proper strong. Clean, powerful, and punchy. For experienced surfers only at that size.
Sunday is where it really cleans up. Morning sees 6ft SW at 14 seconds, with a gentle offshore breeze from the ESE. That’s clean, lined-up, and the energy is still strong (1537). This is the standout window of the first week – excellent conditions for those who know what they’re doing. Sunday afternoon stays clean with 6ft SW.
Monday takes a turn. The wind swings NNW and gets nasty. Morning is 4ft SW but cross-on and choppy. Monday afternoon jumps to 7ft from the NW with a short period of 7 seconds – that’s junky, lumpy, and messy. Poor conditions through to Wednesday morning. Wednesday morning brings back 6ft SW and a cross-off wind, but it’s labelled marginal. The energy is still strong (2217), but the quality isn’t there.
Thursday morning is a bright spot – 6ft SW at 12 seconds with a moderate offshore wind. Clean, good energy (1159). Another call for experienced surfers. Thursday afternoon and Friday are clean but not quite as good.
After that, we hit a gap. From Tuesday the 22nd through to Friday the 25th, the wind is onshore or cross-shore and the surf is small or poor. A solid three to four day lull. Don’t bother paddling out then.
Then, on Saturday the 26th, we get a real curveball. A very long period SW groundswell rolls in – 3ft at 20 seconds in the morning, and 4ft at 19 seconds in the afternoon. That’s a lot of period for not a lot of height. Energy is moderate (1415 and 1567). This kind of long-period groundswell can be weird at a beach break – tends to jack up and close out or go too straight. Might be better for a point or reef, but here at Big Bay, it’s a bit of a wildcard.
Finally, Sunday the 27th brings one more late standout: 8ft from the WSW at 16 seconds, cross-off wind, and very strong energy (2874). Clean, powerful, and big. That’s a legitimate swell for the brave and the skilled. But it’s at the very end of the window, so it’s promising but less certain.
If I had to pick one true standout: Sunday morning, September 13th. 6ft SW, 14 seconds, gentle offshore, clean, and full of power. That’s the one. For a late runner, Sunday September 27th morning is worth watching too.
Rusty.
Short Range ForecastLight rain (total 7mm), mostly falling on Mon morning. Warm (max 22°C on Sun afternoon, min 14°C on Mon night). Winds increasing (calm on Sun night, fresh winds from the NW by Mon afternoon). | Days 4-6 Weather SummaryModerate rain (total 16mm), heaviest on Tue night. Very mild (max 17°C on Tue afternoon, min 12°C on Wed afternoon). Winds decreasing (fresh winds from the NW on Tue afternoon, calm by Tue night). | ||||||||||||||||||||
Saturday 12 | Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | |||||||||||||||
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) | SW 14 | SW 16 | SW 15 | SW 14 | SW 14 | SW 13 | SW 12 | NW 7 | SW 11 | SW 19 | SW 16 | WSW 15 | SW 14 | SW 13 | SW 12 | SW 12 | SW 11 | SW 12 | SW 13 | SW 13 | SW 14 |
Wave Graph | |||||||||||||||||||||
1500 | 3059 | 2650 | 1463 | 1029 | 663 | 430 | 382 | 250 | 171 | 1367 | 3766 | 1233 | 1162 | 773 | 778 | 600 | 752 | 864 | 1613 | 2050 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | off | off | off | cross-off | cross-on | cross-on | cross-on | cross | cross-on | cross-on | cross-on | cross-off | cross-off | cross-off | off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 3:58PM1.68m | 4:17AM1.52m | 4:29PM1.62m | 4:48AM1.45m | 4:59PM1.52m | 5:18AM1.35m | 5:29PM1.40m | 5:49AM1.24m | 6:00PM1.27m | 6:24AM1.13m | 6:36PM1.13m | 7:10AM1.01m | 7:30PM1.00m | ||||||||
Low Tide | 9:48AM0.03m | 10:15PM0.01m | 10:19AM0.08m | 10:45PM0.07m | 10:49AM0.16m | 11:15PM0.17m | 11:18AM0.26m | 11:44PM0.28m | 11:48AM0.38m | 00:15AM0.41m | 12:20PM0.51m | 00:53AM0.53m | 1:03PM0.63m | 2:02AM0.64m | |||||||
6:50 | — | — | 6:48 | — | — | 6:47 | — | — | 6:46 | — | — | 6:43 | — | — | 6:43 | — | — | 6:41 | — | — | |
— | 6:35 | — | — | 6:36 | — | — | 6:36 | — | — | 6:37 | — | — | 6:37 | — | — | 6:37 | — | — | 6:38 | — | |
mm | — | — | — | — | 1 | 2 | 3 | — | 1 | — | — | 9 | 5 | 2 | — | — | — | — | — | — | — |
Temp °C | 18 | 19 | 16 | 20 | 22 | 19 | 18 | 18 | 15 | 16 | 17 | 16 | 13 | 13 | 13 | 15 | 17 | 16 | 15 | 16 | 14 |
Feels °C | 16 | 14 | 13 | 18 | 21 | 20 | 13 | 12 | 10 | 11 | 11 | 13 | 11 | 6 | 8 | 11 | 14 | 13 | 8 | 10 | 9 |
Swell 1 Height (m) Direction Period (s) | SW 14 | SW 16 | SW 15 | SW 14 | SW 14 | SW 13 | SW 12 | SW 12 | SW 11 | SW 11 | SW 16 | WSW 15 | SW 14 | SW 13 | SW 12 | SW 12 | SW 11 | SW 12 | SW 13 | SW 13 | SW 14 |
1500 | 3059 | 2650 | 1463 | 1029 | 663 | 430 | 309 | 250 | 168 | 1367 | 3766 | 1233 | 1162 | 773 | 778 | 600 | 752 | 864 | 1613 | 2050 | |
Swell 2 Height (m) Direction Period (s) | — | — | SSE 7 | S 8 | S 7 | S 7 | SE 9 | SSE 13 | SW 18 | SW 19 | WSW 7 | NW 6 | SW 9 | WSW 13 | W 13 | SSE 7 | W 12 | W 11 | SW 15 | — | — |
— | — | 202 | 74 | 68 | 37 | 12 | 16 | 12 | 171 | 81 | 19 | 573 | 638 | 402 | 79 | 104 | 21 | 421 | — | — | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | SE 13 | SW 14 | — | — | WSW 13 | — | — | W 12 | — | — | W 11 | — | — |
— | — | — | — | — | — | — | — | 7 | 74 | — | — | 411 | — | — | 144 | — | — | 9 | — | — | |
Wind waves Height (m) Direction Period (s) | S 8 | SSE 8 | — | — | — | NNW 3 | NW 5 | NW 7 | NW 7 | NW 6 | NW 6 | — | — | S 6 | SSE 7 | SE 7 | SSE 6 | SSE 6 | S 6 | S 6 | SSE 5 |
273 | 324 | — | — | — | 3 | 110 | 382 | 209 | 120 | 136 | — | — | 252 | 189 | 158 | 64 | 55 | 123 | 187 | 53 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 129 | 0 | 0 | 0 | 2 | 95 | 399 | 87 | 232 | 232 | 2 | 9 | 56 | 0 | 0 | 0 | 0 | 322 | 419 | 15 |
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.










