Surf Forecasts:
Backdoor 4 surf forecast from 16 Sep 2026:
- Best quality surf: Thursday 17 Sep, 1AM (local time) - 13ft (4.0m), 11s period, S swell with offshore winds.
- Most powerful swell: Thursday 17 Sep, 1AM (local time) - 13ft (4.0m), 11s period, S swell with 3,278 kJ wave energy.
- Next surfable swell (1★+): Thursday 17 Sep, 1AM (local time) - 13ft (4.0m), 11s period with S swell.
Best Forecast Surf Conditions for Backdoor 4 this week:
The surf forecast for Backdoor 4 over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Thursday (Sep 17) at 1AM. The primary swell is predicted to be 4.0m and 11s period with a secondary swell of 0.1m and 13s. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Backdoor 4 in the next 16 days are 4.0m 11s and forecast to arrive on Thursday (Sep 17) at 1AM. 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 5s period and expected on Monday (Sep 21) at 7PM.
| Wave Type | Time (AEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 1AM (Thu 17th Sep) | 13ft (4.0m) 11s |
| Best Surf | 1AM (Thu 17th Sep) | 13ft (4.0m) 11s |
| Most Powerful | 1AM (Thu 17th Sep) | 13ft (4.0m) 11s |
Table - best surf conditions forecast for Backdoor 4 over the next 16 days.
The Lowdown
Alright, this is Rusty. Let's talk about what we've got on the menu.
We’re looking at a solid start to the run, but there’s a long, quiet stretch after the first few days. The real action is all at Backdoor 4 (Big Island) , a very consistent, exposed reef that loves an easterly swell. The water temp is sitting at 65°F, which is pretty much average for this time of year, so nothing weird going on there.
The standout window hits on Friday, September 18th, in the morning. We’ve got a clean 5ft south swell pushing in with a 9-second period, but the magic is the wind – it’s going glassy. Absolutely dead calm. The combined energy is moderate at (439), and that's the moment to be in the water. That’s your best shot.
The afternoon of the 18th gets messy with a cross-on wind, so don’t sleep in.
The run up to that is big. On Wednesday the 16th, we’ve got a massive 12ft south swell with a 10-second period and very strong energy (2754). The wind is howling offshore at 25 mph. That’s clean, but it’s way too big – only for experts. Thursday stays oversized with a 10ft swell.
After Friday morning, the surf drops off fast. The weekend of the 19th and 20th is tiny, with weak, long-period south swells and cross-on winds. Not worth it. The following week from Monday the 21st through to the end of September is a dead zone – days of poor conditions, small waves, and onshore wind.
You’re looking at a long, quiet gap of about 10 days with nothing worth paddling out for. The run from the 1st of October picks up a little with a 6ft south swell and moderate energy (778) on the afternoon, but the wind is cross-shore and it’s still only marginal.
So, bottom line: Friday the 18th morning for that glassy, clean 5ft south swell. That’s the one. The rest is mostly a wait.
Rusty.
Short Range ForecastSome drizzle, heaviest during Thu morning. Warm (max 26°C on Sat morning, min 10°C on Wed night). Winds decreasing (strong winds from the S on Wed afternoon, calm by Fri morning). | Days 5-7 Weather SummaryMostly dry. Warm (max 29°C on Mon morning, min 15°C on Mon night). Winds increasing (calm on Sat afternoon, fresh winds from the S by Mon afternoon). | |||||||||||||||||||
Wed 16 | Thursday 17 | Friday 18 | Saturday 19 | Sunday 20 | Monday 21 | Tuesday 22 | ||||||||||||||
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) | S 10 | S 11 | S 10 | SSE 9 | SSE 9 | S 9 | S 10 | S 16 | S 17 | S 9 | S 10 | S 11 | S 19 | S 18 | S 13 | S 13 | SSE 8 | S 12 | S 11 | S 19 |
Wave Graph  | ||||||||||||||||||||
 kJ | 2738 | 3278 | 1864 | 1019 | 477 | 311 | 347 | 185 | 204 | 109 | 71 | 274 | 854 | 336 | 321 | 573 | 308 | 240 | 229 | 270 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | off | cross-off | cross-off | cross | glassy | cross-on | cross | cross | cross-on | cross-off | cross-on | cross-on | cross-on | cross-on | off | off | cross-off | cross-off | glassy |
High Tide | 11:39PM1.01m | 11:59AM1.34m | 00:34AM0.92m | 12:54PM1.27m | 1:48AM0.86m | 2:04PM1.24m | 3:16AM0.87m | 3:16PM1.25m | 4:27AM0.92m | 4:18PM1.29m | 5:17AM1.00m | 5:08PM1.36m | ||||||||
Low Tide | 5:51PM0.39m | 5:18AM0.46m | 6:50PM0.46m | 6:02AM0.53m | 8:02PM0.50m | 7:03AM0.59m | 9:21PM0.50m | 8:23AM0.62m | 10:27PM0.45m | 9:41AM0.59m | 11:15PM0.38m | 10:43AM0.53m | 11:53PM0.30m | |||||||
 |  |  | |  | | | | | | | | | |  | |  | | |  | |
 | — | — | 5:50 | — | — | 5:50 | — | — | 5:48 | — | — | 5:47 | — | — | 5:46 | — | — | 5:43 | — | — |
 | 5:45 | — | — | 5:45 | — | — | 5:45 | — | — | 5:46 | — | — | 5:47 | — | — | 5:47 | — | — | 5:49 | — |
mm | — | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 4 |
Temp °C | 15 | 15 | 14 | 14 | 13 | 17 | 17 | 17 | 26 | 27 | 23 | 21 | 20 | 22 | 29 | 16 | 16 | 17 | 17 | 17 |
Feels °C | 5 | 6 | 9 | 11 | 11 | 12 | 13 | 14 | 22 | 23 | 19 | 17 | 18 | 17 | 26 | 11 | 12 | 16 | 16 | 14 |
Swell 1 Height (m) Direction Period (s) | ENE 13 | E 13 | E 13 | SSE 9 | SSE 9 | S 9 | S 10 | S 9 | S 10 | S 9 | S 10 | S 11 | S 19 | S 18 | S 13 | E 11 | S 12 | SSE 8 | S 11 | SSE 9 |
| kJ | 16 | 3 | 3 | 1019 | 477 | 311 | 347 | 175 | 151 | 109 | 71 | 274 | 854 | 336 | 321 | 2 | 181 | 240 | 229 | 197 |
Swell 2 Height (m) Direction Period (s) | — | — | NE 13 | S 19 | E 13 | SE 8 | SE 7 | S 16 | S 17 | S 15 | S 18 | SSE 5 | S 8 | S 11 | SSE 18 | — | S 21 | S 12 | SSE 7 | S 19 |
| kJ | — | — | 7 | 7 | 3 | 69 | 54 | 185 | 204 | 69 | 24 | 24 | 116 | 114 | 60 | — | 8 | 221 | 91 | 270 |
Swell 3 Height (m) Direction Period (s) | — | — | — | E 13 | S 19 | S 18 | S 18 | SE 8 | SE 7 | SE 8 | SE 7 | SSE 20 | E 11 | S 7 | NNW 3 | — | S 18 | S 20 | S 19 | S 11 |
| kJ | — | — | — | 3 | 7 | 59 | 97 | 28 | 14 | 9 | 2 | 131 | 3 | 26 | 1 | — | 6 | 31 | 62 | 59 |
Wind waves Height (m) Direction Period (s) | S 10 | S 11 | S 10 | — | — | — | — | W 3 | WNW 3 | — | SSW 10 | — | E 4 | — | — | S 13 | SSE 8 | — | — | — |
| kJ | 2738 | 3278 | 1864 | — | — | — | — | 2 | 1 | — | 128 | — | 17 | — | — | 573 | 308 | — | — | — |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 787 | 168 | 0 | 0 | 0 | 0 | 37 | 2 | 0 | 3 | 0 | 9 | 37 | 0 | 2 | 338 | 0 | 0 | 0 | 0 |
Best forecast wave conditions in Newcastle | ||||||||||||||||||||
Best forecast wave conditions in Australia | ||||||||||||||||||||
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Information about the Backdoor 4 Surf forecast
The above surf forecast table for Backdoor 4 provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Backdoor 4 can be found by selecting the local surf guide option on the grey menu. Our Backdoor 4 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 (Backdoor 4) 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 Backdoor 4 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.
Backdoor 4 is 14 km (9 miles) from the city of Catherine Hill Bay. If you plan a holiday in Newcastle, look for hotels and other accommodation in Catherine Hill Bay. Catherine Hill Bay has rooms for a wide range of budgets as well as car hire and transport links.
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