Surf Forecasts:
Backdoor 4 surf forecast from 12 Sep 2026:
- Best quality surf: Wednesday 16 Sep, 4AM (local time) - 10ft (3.0m), 8s period, S swell with offshore winds.
- Most powerful swell: Wednesday 16 Sep, 7PM (local time) - 13ft (4.0m), 10s period, S swell with 3,075 kJ wave energy.
- Next surfable swell (1★+): Tuesday 15 Sep, 7AM (local time) - 3ft (0.9m), 6s period with ENE 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 Tuesday (Sep 15) at 7AM. The primary swell is predicted to be 0.9m and 6s period with a secondary swell of 0.4m and 10s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Backdoor 4 in the next 16 days are 4.0m 10s and forecast to arrive on Wednesday (Sep 16) at 7PM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 6s period and expected on Tuesday (Sep 15) at 7PM.
| Wave Type | Time (AEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 7AM (Tue 15th Sep) | 3ft (0.9m) 6s |
| Best Surf | 4AM (Wed 16th Sep) | 10ft (3.0m) 8s |
| Most Powerful | 7PM (Wed 16th Sep) | 13ft (4.0m) 10s |
Table - best surf conditions forecast for Backdoor 4 over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s run it down for Backdoor 4 (Oahu).
The next two weeks are a mixed bag, with a big, powerful swell coming, but you’ve got to be patient. The first clean, rideable window doesn’t open until the morning of Tuesday, September 15th. Before that, it’s all small, weak junk and bad wind – nothing worth suiting up for.
Tuesday morning the 15th, a small 3ft swell from the ENE rolls in. With a clean S offshore breeze, it’ll be glassy and fun on a longboard or a small fish. Don’t expect much power – the energy is only 92 (weak).
But here’s the main event. Wednesday, September 16th is a monster day. A serious S groundswell pushes through – starting at 12ft in the morning and hitting a solid 13ft in the afternoon. The energy readings are massive: 1956 and then 2968 (very strong). The wind is howling offshore from the SSW at 25 mph, keeping the surface clean and lined up. This is deep, expert-only territory. The swell is coming from the S, and the break prefers E, so it’s not a perfect match, but the size alone will be staggering. For sheer power and consequence, this is it.
Thursday the 17th stays heavy, with 10ft to 8ft from the S, still with clean offshore winds and very high energy (1665 and 1051). Still a big-wave day for the crew.
Things drop off sharply after that. Saturday morning September 19th offers a nice change of pace – a 4ft ESE groundswell (11-second period) with glassy, clean conditions. This is a much more manageable and fun wave for a wider range of surfers, with moderate energy (445).
Word to the wise: the water is about 65°F, right on average for the season, so you’ll want a spring suit or a 4/3.
In short: if you’re a charger, you live for September 16th and 17th. If you want a clean, fun session with no ego, aim for the Saturday mornings on September 19th and 22nd.
Rusty
Short Range ForecastMostly dry. Warm (max 23°C on Mon morning, min 13°C on Sat night). Winds increasing (calm on Sat morning, fresh winds from the NE by Sun afternoon). | Days 4-6 Weather SummaryModerate rain (total 13mm), heaviest on Tue night. Very mild (max 19°C on Tue morning, min 10°C on Wed night). Winds decreasing (strong winds from the SSW on Wed morning, light winds from the WNW by Thu 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) | S 12 | SSE 11 | S 20 | S 10 | S 11 | S 10 | S 12 | NE 6 | NE 6 | ENE 7 | ENE 6 | S 7 | S 9 | S 10 | S 10 | S 9 | S 9 | S 8 | S 8 | ESE 10 | ESE 10 |
Wave Graph  | |||||||||||||||||||||
 kJ | 425 | 376 | 198 | 164 | 146 | 138 | 132 | 176 | 177 | 59 | 27 | 467 | 1946 | 2952 | 2408 | 1655 | 842 | 401 | 223 | 325 | 370 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | cross-on | on | cross-on | cross-on | on | cross-on | cross-on | on | off | cross-off | off | off | off | off | cross-off | off | cross-off | on | cross-on | cross-off |
High Tide | 8:54PM1.50m | 9:21AM1.49m | 9:34PM1.38m | 9:57AM1.49m | 10:13PM1.25m | 10:34AM1.46m | 10:54PM1.12m | 11:13AM1.40m | 11:39PM1.01m | 11:59AM1.34m | 00:34AM0.92m | 12:54PM1.27m | 1:48AM0.86m | ||||||||
Low Tide | 2:47PM0.17m | 3:07AM0.11m | 3:31PM0.19m | 3:39AM0.19m | 4:15PM0.24m | 4:10AM0.28m | 5:01PM0.31m | 4:42AM0.37m | 5:51PM0.39m | 5:18AM0.46m | 6:50PM0.46m | 6:02AM0.53m | 8:02PM0.50m | ||||||||
 | |  | |  | | | | | | |  |  |  | | | | | | | | |
 | 5:58 | — | — | 5:56 | — | — | 5:54 | — | — | 5:54 | — | — | 5:52 | — | — | 5:50 | — | — | 5:50 | — | — |
 | — | 5:42 | — | — | 5:43 | — | — | 5:44 | — | — | 5:44 | — | — | 5:45 | — | — | 5:45 | — | — | 5:45 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | 4 | 1 | 2 | 4 | 1 | 1 | — | — | — | — |
Temp °C | 17 | 17 | 16 | 17 | 18 | 17 | 23 | 21 | 21 | 19 | 16 | 14 | 13 | 14 | 14 | 11 | 14 | 14 | 17 | 17 | 15 |
Feels °C | 14 | 14 | 13 | 13 | 13 | 13 | 17 | 18 | 18 | 16 | 13 | 7 | 4 | 4 | 6 | 5 | 9 | 12 | 12 | 12 | 15 |
Swell 1 Height (m) Direction Period (s) | S 12 | SSE 11 | S 10 | S 10 | S 11 | S 10 | S 12 | S 11 | NE 6 | ENE 7 | ENE 6 | NE 6 | NE 12 | ENE 13 | E 13 | E 13 | ESE 8 | S 8 | S 8 | ESE 10 | ESE 10 |
| kJ | 425 | 376 | 161 | 164 | 146 | 138 | 132 | 82 | 101 | 59 | 27 | 11 | 6 | 16 | 3 | 3 | 178 | 401 | 223 | 325 | 370 |
Swell 2 Height (m) Direction Period (s) | S 19 | S 18 | S 20 | ENE 5 | S 16 | ENE 13 | NE 6 | ENE 13 | S 10 | S 10 | S 9 | E 14 | E 15 | — | — | NE 13 | S 19 | ESE 8 | ESE 8 | S 8 | S 9 |
| kJ | 186 | 156 | 198 | 13 | 43 | 17 | 33 | 16 | 50 | 30 | 15 | 15 | 4 | — | — | 7 | 28 | 173 | 130 | 138 | 129 |
Swell 3 Height (m) Direction Period (s) | ENE 14 | ENE 14 | ENE 13 | S 17 | ENE 13 | S 18 | ENE 13 | — | E 12 | E 13 | E 13 | E 9 | — | — | — | — | E 13 | E 13 | ESE 10 | SSE 18 | S 17 |
| kJ | 19 | 18 | 16 | 53 | 17 | 6 | 17 | — | 12 | 3 | 14 | 2 | — | — | — | — | 3 | 3 | 74 | 109 | 147 |
Wind waves Height (m) Direction Period (s) | — | ENE 2 | NE 5 | NE 5 | ENE 5 | NE 6 | NE 6 | NE 6 | NE 6 | — | S 5 | S 7 | S 9 | S 10 | S 10 | S 9 | S 9 | — | — | — | N 4 |
| kJ | — | 1 | 35 | 17 | 77 | 120 | 75 | 176 | 177 | — | 25 | 467 | 1946 | 2952 | 2408 | 1655 | 842 | — | — | — | 9 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 37 | 2 | 2 | 552 | 2 | 2 | 19 | 2 | 0 | 218 | 215 | 781 | 787 | 248 | 0 | 0 | 0 | 2 | 91 | 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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