Surf Forecasts:
Backdoor surf forecast from 18 Aug 2026:
- Best quality surf: Friday 21 Aug, 5AM (local time) - 1.5ft (0.5m), 16s period, SW swell with cross-offshore winds.
- Most powerful swell: Saturday 22 Aug, 11PM (local time) - 2.5ft (0.8m), 13s period, WNW swell with 195 kJ wave energy.
- Next surfable swell (1★+): Friday 21 Aug, 5AM (local time) - 1.5ft (0.5m), 16s period with SW swell.
Best Forecast Surf Conditions for Backdoor this week:
The surf forecast for Backdoor over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Friday (Aug 21) at 5AM. The primary swell is predicted to be 0.5m and 16s period with a secondary swell of 0.7m and 6s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Backdoor in the next 16 days are 0.8m 13s and forecast to arrive on Saturday (Aug 22) at 11PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 2.2m 7s period and expected on Monday (Aug 24) at 8PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 5AM (Fri 21st Aug) | 1.5ft (0.5m) 16s |
| Best Surf | 5AM (Fri 21st Aug) | 1.5ft (0.5m) 16s |
| Most Powerful | 11PM (Sat 22nd Aug) | 2.5ft (0.8m) 13s |
Table - best surf conditions forecast for Backdoor over the next 16 days.
The Lowdown
Alright, this is Rusty.
Let's be straight with each other: looking at the next 16 days from Monday the 17th of August, the only spot we have to talk about is Backdoor, and it's not much of a story. We're looking at a long stretch of what can only be called poor surf conditions, with nothing really to grab onto.
Starting Monday afternoon, we’re stuck with tiny, weak waves measuring 0.7 ft to 1.0 ft. The water temp is 80°, which is about normal for the time of year. The wave energy is laughably low, sitting in the teens and twenties – there's simply no power behind it. By Saturday morning the 22nd, energy climbs to 117 with a 2 ft west swell, but the condition is still poor. On Sunday the 23rd, we see a bump to 3 ft from the WNW with energy hitting 168 (moderate), but winds are blowing a stiff 19 mph cross-off, making it messy.
Even on the best-looking day, Wednesday morning the 26th of August, the swell is only 0.7 ft with energy at 32. It's just not enough. The whole run is dominated by persistent cross-off winds from the east, mostly in the 12 to 19 mph range, which is a real bummer. Given the tiny waves and constant wind, this setup screams kite surfing more than paddle surfing.
If you're really itching to get wet, keep an eye on Monday the 31st of August. That's when the strongest energy of the whole run shows up at 133, with 1 ft of WNW swell. The period is 15 seconds—a very long groundswell—which could bring a few clean, lined-up waves to the reef at Backdoor. But with 19 mph cross-off winds, it'll still be a scrap. That's your best, but it's a long way off and far from a sure thing.
Plain and simple: the first week is a total bust, and the second week offers only a tiny hope. It’s a quiet period, so don't push it.
Rusty.
Short Range ForecastMostly dry. Warm (max 26°C on Mon afternoon, min 24°C on Mon night). Wind will be generally light. | Days 5-7 Weather SummaryMostly dry. Warm (max 27°C on Thu afternoon, min 24°C on Thu night). Winds increasing (calm on Thu night, fresh winds from the E by Sat night). | |||||||||||||||||||
Mon 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | ||||||||||||||
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) | W 12 | SW 6 | WNW 13 | WNW 13 | WNW 12 | SW 16 | WNW 11 | NE 6 | NE 6 | NNE 7 | NNE 7 | NE 7 | W 10 | SW 16 | WNW 10 | W 12 | WNW 12 | WNW 11 | NW 11 | NW 11 |
Wave Graph | ||||||||||||||||||||
11 | 6 | 17 | 34 | 28 | 41 | 25 | 40 | 40 | 38 | 40 | 44 | 19 | 124 | 33 | 73 | 167 | 160 | 121 | 117 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | glassy | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 4:19PM0.52m | 7:40AM0.53m | 3:28PM0.49m | 10:00AM0.55m | 11:33AM0.60m | 12:16PM0.64m | 12:49PM0.67m | 1:16PM0.70m | 11:38PM0.32m | |||||||||||
Low Tide | 11:40PM0.17m | 12:35PM0.47m | 00:09AM0.17m | 00:51AM0.18m | 2:10AM0.18m | 3:50AM0.17m | 5:00AM0.14m | 9:01PM0.30m | ||||||||||||
— | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | |
7:00 | — | — | 7:00 | — | — | 6:59 | — | — | 6:59 | — | — | 6:58 | — | — | 6:57 | — | — | 6:55 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 26 | 25 | 25 | 26 | 25 | 25 | 26 | 24 | 26 | 27 | 25 | 26 | 27 | 26 | 26 | 27 | 25 | 26 | 26 | 25 |
Feels °C | 26 | 25 | 25 | 25 | 25 | 25 | 27 | 25 | 28 | 28 | 27 | 28 | 29 | 29 | 27 | 27 | 25 | 25 | 25 | 24 |
Swell 1 Height (m) Direction Period (s) | WSW 6 | E 9 | WNW 13 | NE 8 | WNW 12 | WNW 12 | WNW 11 | E 8 | E 8 | E 8 | E 7 | NE 7 | SW 16 | SW 16 | SSW 16 | W 12 | WNW 12 | WNW 11 | NW 11 | NW 11 |
4 | 15 | 17 | 15 | 28 | 28 | 25 | 82 | 78 | 90 | 70 | 44 | 64 | 124 | 98 | 73 | 167 | 160 | 121 | 117 | |
Swell 2 Height (m) Direction Period (s) | S 14 | SW 6 | SSW 17 | WNW 13 | NNE 7 | SW 16 | SSW 16 | NE 6 | NE 6 | NNE 7 | NNE 7 | E 7 | W 10 | W 10 | WNW 10 | SW 16 | SW 15 | SW 15 | SW 15 | SW 14 |
16 | 6 | 28 | 34 | 9 | 41 | 25 | 40 | 40 | 38 | 40 | 48 | 19 | 31 | 33 | 63 | 60 | 57 | 54 | 51 | |
Swell 3 Height (m) Direction Period (s) | W 12 | S 14 | WSW 6 | SSW 18 | SSW 18 | WSW 7 | SSW 19 | SW 16 | SW 18 | SW 17 | SSW 16 | SSW 16 | ESE 8 | WSW 10 | WSW 10 | WNW 15 | WSW 9 | WSW 9 | WSW 9 | SW 8 |
11 | 15 | 4 | 30 | 30 | 4 | 35 | 67 | 79 | 76 | 104 | 107 | 14 | 10 | 10 | 44 | 8 | 8 | 8 | 3 | |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 7 | ENE 7 | E 6 | ENE 7 | ENE 7 | ENE 8 | — | — | — | — | — | ENE 7 | ENE 7 | E 6 | E 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 |
284 | 203 | 186 | 115 | 186 | 137 | 176 | — | — | — | — | — | 113 | 118 | 124 | 156 | 308 | 301 | 268 | 316 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 26 | 26 | 24 | 24 | 24 | 2 | 6 | 24 | 0 | 0 | 0 | 0 | 0 | 2 | 10 | 2 | 2 | 24 | 165 | 26 |
Best forecast wave conditions in Oahu | ||||||||||||||||||||
Best forecast wave conditions in United States | ||||||||||||||||||||
Header Global | ||||||||||||||||||||
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Information about the Backdoor Surf forecast
The above surf forecast table for Backdoor provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Backdoor can be found by selecting the local surf guide option on the grey menu. Our Backdoor 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) 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 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 is 19 km (12 miles) from Wahiawa. If you plan a vacation in Oahu, look for hotels and other accommodation in Wahiawa. Wahiawa has rooms for a wide range of budgets as well as car hire and transport links.











