Surf Forecasts:
Onrus surf forecast from 18 Aug 2026:
- Best quality surf: Tuesday 18 Aug, 5PM (local time) - 10ft (3.0m), 13s period, SW swell with onshore winds.
- Most powerful swell: Saturday 22 Aug, 8PM (local time) - 13ft (4.0m), 13s period, SW swell with 5,753 kJ wave energy.
- Next surfable swell (1★+): Tuesday 18 Aug, 8AM (local time) - 7.5ft (2.3m), 13s period with SW swell.
Best Forecast Surf Conditions for Onrus this week:
The surf forecast for Onrus over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Tuesday (Aug 18) at 8AM. The primary swell is predicted to be 2.3m and 13s period with a secondary swell of 1.4m and 13s. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Onrus 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 1.9m 6s period and expected on Saturday (Aug 22) at 8AM.
| Wave Type | Time (SAST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8AM (Tue 18th Aug) | 7.5ft (2.3m) 13s |
| Best Surf | 5PM (Tue 18th Aug) | 10ft (3.0m) 13s |
| Most Powerful | 8PM (Sat 22nd Aug) | 13ft (4.0m) 13s |
Table - best surf conditions forecast for Onrus over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let's have a look at what's cookin' for Onrus over the next couple of weeks.
Right off the bat, the water is sittin' at 57.4°, which is a bit colder than we're used to for this time of year. That anomaly of -2.9° is a solid reminder we're in for a bit of a chill, so don't forget the rubber.
The next sixteen days are a bit of a rollercoaster, with some absolute monsters mixed in with some real clean windows. The big story here is that we’ve got some seriously heavy, high-energy swell pulses comin' through, with combined energy readings up in the thousands, like 2650 and 3078 on the 18th and 20th of August. But here’s the thing – a lot of that juice is goin' to be too much for this reef. Onrus is a reef setup, and when the swell gets over 8.2ft, it’s for experts only. When it hits 9.8ft or more, it’s a full-on beast.
Let’s start with the early days. Tuesday the 18th is a washout for paddle surfin'. Morning brings a 7.9ft SW swell with a light onshore breeze, but the conditions are marginal. The afternoon? 9.8ft of SW groundswell with a 13-second period. The wind and tide are right, but that’s just too big for a comfortable session.
Wednesday the 19th offers a glimmer. The mornin' is still a bit messy with a cross-shore wind on that 7.9ft swell. But the afternoon? That’s where it’s at. The swell drops to a still-chunky 7.5ft from the SW, period at 12 seconds, and the wind goes light cross-offshore. This is clean, excellent surf for experienced surfers. This is your best bet for the first few days. The crowd factor here is 'sometimes', so you might have company, but that’s the price for a quality reef.
Thursday the 20th sees another spike of big energy – 9.8ft again in the mornin' – so it’s a no-go for most.
Now, if you’re an expert, hold onto your board. Saturday the 22nd of August is a standout. The afternoon delivers a massive 13.1ft SW swell with a 13-second period and combined energy of 5432. That is a serious amount of water movin'. The wind is cross-offshore and clean. This is a big, powerful, expert-only wave. It’s not for the faint of heart.
Sunday the 23rd of August is another one for the big-wave chargers. The mornin' is glassy, dead calm with a 9.8ft SW swell. Absolutely clean conditions, but again, that size is intimidatin' and for experts only. The energy readin' is 2960. It’s a beautiful, terrifyin' sight.
After that massive weekend, things settle down. Monday the 24th gives us a very nice, clean 4.6ft WSW swell with glassy conditions in the mornin'. That’s a much more user-friendly size, and the conditions are excellent.
We hit a bit of a lull mid-week. Tuesday the 25th is a write-off with strong cross-onshore wind and poor conditions. Wednesday the 26th, however, is a gem. Mornin' glass, a clean 6.2ft SW swell with a 13-second period. This is excellent for experienced surfers. The afternoon stays glassy with a 5.2ft swell. Perfect.
Thursday the 27th keeps the good vibes rollin' with a clean, cross-offshore wind and a 4.3ft WSW swell in the afternoon. Very good conditions.
Friday the 28th and Saturday the 29th turn ugly again with strong onshore winds and poor conditions as a big, long-period (17-second!) WSW swell builds.
Sunday the 30th of August is another big one. A 11.5ft SW swell with a 14-second period and combined energy of 4201. The wind is cross-shore, but it’s a fresh breeze makin' it lumpy. For the experts who want power, it's there, but the quality is compromised by the wind.
Lookin' into the start of September, we finally get a prolonged period of clean, manageable waves. Monday the 31st of August and Tuesday the 1st of September are the true standouts of the entire forecast. On Monday, we have a 7.2ft SW swell with a light cross-offshore breeze. Tuesday mornin' is even better: a 6.9ft SW swell with a glassy, calm wind. Both are clean, excellent conditions for experienced surfers. This is the sweet spot – decent size, perfect wind, and good energy. The combined energy is still in the 1100-1400 range, so it’s got some punch. This is the window to circle on your calendar.
The forecast ends on a cautionary note. Wednesday the 2nd of September brings another massive 11.5ft SW swell, but this time the wind is a mess.
So, to wrap it up: the first week is a mix of too big or marginal. Your early pick is Wednesday afternoon the 19th. The real gold is at the very end of August and the start of September, specifically Monday the 31st of August and Tuesday the 1st of September. Keep an eye on the long-range for those dates – they’re lookin'
Short Range ForecastMostly dry. Very mild (max 16°C on Tue afternoon, min 10°C on Thu night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 2mm), mostly falling on Sat morning. Very mild (max 18°C on Fri afternoon, min 10°C on Fri morning). Winds decreasing (strong winds from the NW on Sat morning, calm by Sun morning). | ||||||||||||||||||||
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) | SW 12 | SW 13 | SW 12 | SW 12 | SW 12 | SW 12 | SW 13 | SW 12 | SW 12 | SW 11 | SSW 11 | WSW 11 | WSW 10 | SW 13 | SW 13 | SW 12 | SW 11 | SW 11 | WSW 12 | WSW 11 | SW 13 |
Wave Graph | |||||||||||||||||||||
1768 | 2458 | 2148 | 1665 | 1451 | 1878 | 3078 | 2218 | 1249 | 882 | 394 | 311 | 1420 | 5432 | 4418 | 2244 | 1642 | 1172 | 497 | 370 | 1240 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | cross-on | cross | cross-off | cross-off | on | on | cross-on | cross-on | cross-on | off | off | cross-off | off | glassy | cross-on | glassy | glassy | cross-on | cross-on |
High Tide | 6:46PM1.33m | 7:08AM1.13m | 7:25PM1.19m | 7:59AM1.02m | 8:25PM1.07m | 9:40AM0.94m | 10:21PM1.01m | 11:56AM0.98m | 00:08AM1.06m | 1:01PM1.09m | 1:04AM1.17m | 1:39PM1.22m | 1:42AM1.27m | ||||||||
Low Tide | 12:28PM0.39m | 1:06AM0.45m | 1:02PM0.53m | 1:50AM0.57m | 1:50PM0.65m | 3:11AM0.66m | 3:39PM0.74m | 5:33AM0.65m | 6:08PM0.70m | 6:49AM0.56m | 7:10PM0.59m | 7:30AM0.44m | 7:48PM0.48m | ||||||||
7:20 | — | — | 7:18 | — | — | 7:16 | — | — | 7:16 | — | — | 7:15 | — | — | 7:13 | — | — | 7:13 | — | — | |
— | 6:14 | — | — | 6:15 | — | — | 6:15 | — | — | 6:15 | — | — | 6:16 | — | — | 6:17 | — | — | 6:17 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 1 | — | — | — | — | — | — | — |
Temp °C | 15 | 16 | 13 | 14 | 15 | 13 | 15 | 15 | 12 | 15 | 18 | 13 | 14 | 16 | 14 | 13 | 15 | 12 | 14 | 15 | 12 |
Feels °C | 14 | 14 | 9 | 13 | 13 | 11 | 14 | 13 | 9 | 13 | 16 | 13 | 7 | 9 | 12 | 12 | 13 | 11 | 13 | 14 | 11 |
Swell 1 Height (m) Direction Period (s) | SW 12 | SW 13 | SW 12 | SW 12 | SW 12 | SW 12 | SW 13 | SW 12 | SW 12 | SW 11 | SSW 11 | WSW 11 | — | SW 13 | SW 13 | SW 12 | SW 11 | SW 11 | WSW 12 | SSW 10 | SW 13 |
1768 | 2458 | 2148 | 1665 | 1451 | 1878 | 3078 | 2218 | 1249 | 882 | 394 | 311 | — | 5432 | 4418 | 2244 | 1642 | 1172 | 497 | 320 | 1240 | |
Swell 2 Height (m) Direction Period (s) | SW 12 | E 11 | E 10 | E 10 | E 10 | — | — | — | — | SSW 11 | WSW 11 | SSW 11 | — | — | — | SSW 11 | — | SSW 10 | SSW 10 | WSW 11 | SW 16 |
882 | 9 | 2 | 2 | 2 | — | — | — | — | 387 | 379 | 265 | — | — | — | 716 | — | 502 | 325 | 370 | 326 | |
Swell 3 Height (m) Direction Period (s) | E 11 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | SSW 14 | W 11 |
9 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 127 | 62 | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | E 3 | ENE 3 | — | WNW 4 | WSW 10 | — | — | — | — | — | — | — | — |
— | — | — | — | — | — | — | — | 2 | 3 | — | 21 | 1420 | — | — | — | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 25 | 32 | 10 | 32 | 0 | 0 | 30 | 272 | 10 | 4 | 25 | 0 | 73 | 73 | 25 | 10 | 32 | 0 | 0 | 4 | 10 |
Best forecast wave conditions in Overberg | |||||||||||||||||||||
Best forecast wave conditions in South Africa | |||||||||||||||||||||
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Information about the Onrus Surf forecast
The above surf forecast table for Onrus provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Onrus can be found by selecting the local surf guide option on the grey menu. Our Onrus 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 (Onrus) 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 Onrus 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.
Onrus is 6 km (4 miles) from Hermanus. If you plan a holiday in Overberg, look for hotels and other accommodation in Hermanus. Hermanus has rooms for a wide range of budgets as well as car hire and transport links.











