
Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 15 Jul 2026:
- Most powerful swell: Monday 20 Jul, 11PM (local time) - 4.5ft (1.3m), 7s period, NNW swell with 166 kJ wave energy.
Best Forecast Surf Conditions for Guethary - Les Alcyons/Avalanche this week:
The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 1.3m 7s and forecast to arrive on Monday (Jul 20) at 11PM. Winds are predicted to be cross-shore at the time the swell arrives.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 11PM (Mon 20th Jul) | 4.5ft (1.3m) 7s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what’s coming down the line for the next couple of weeks.
Honestly, I’ve got to be straight with you – this is a grim stretch for Guethary - Les Alcyons/Avalanche. This is a top-shelf reef break that demands a solid, clean swell, and we’re just not getting it. The whole 16-day window is a write-off. There’s no real surf on offer. We’re talking about a long, dry gap from the start all the way through.
We’ve got persistent small, weak, and short-period windswell. The first week is a total struggle. Morning of the 15th you’re looking at a junky 2ft from the NW with a cross-onshore wind – that’s a mess. The water temp is sitting at 78°, which is a full 9° warmer than normal for this time of year, so it’s weirdly warm, but that doesn’t help the waves. The wind stays on it or cross-onshore for days, and the energy readings are all in the weak teens and twenties. You’ll see a bit of glass on the morning of the 18th, but with only 2ft on tap, it’s barely a ripple.
The middle of the week brings a slight bump. The morning of the 20th shows the strongest energy we’ll see for a while at 4ft and moderate energy (111), but the wind is cross-onshore, wrecking the shape. It’s still poor surf. We get a glassy morning on the 23rd with another 4ft, but the swell periods are short and the energy is still low (91). It’s just not enough to get this reef doing its thing.
Now, the one standout, and it’s a big “if” because it’s over a week away, is the 25th of July. The swell finally kicks up to 7ft from the WNW with a period of 7 seconds. The combined energy jumps to strong (361). But, and it’s a big but, the wind is a moderate cross-onshore breeze from the W at 12 mph. For a spot like this that needs that perfect offshore (SE) wind, a choppy 7ft is going to be a washing machine. This is expert-only territory at that size, and with the wind on it, it’s going to be a battle. The conditions are described as “poor surf conditions” across the board for a reason.
The last few days of the month fade back into the small stuff. There’s a morning of glass on the 28th, but it’s only 2ft. There’s simply nothing to get excited about here. Don’t bother paddling out for this one – it’s a blank run. The setup is a beach-and-reef mix, but with the persistent onshore wind and small, weak swell, it’s more interesting for the kite crowd than us paddle surfers. Forecasts can change, but right now, this is a tough one to swallow.
Rusty.
Short Range ForecastMostly dry. Warm (max 23°C on Wed afternoon, min 19°C on Wed night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 24°C on Mon afternoon, min 19°C on Sat morning). Wind will be generally light. | ||||||||||||||||||||
Wednesday 15 | Thursday 16 | Friday 17 | Saturday 18 | Sunday 19 | Monday 20 | Tuesday 21 | |||||||||||||||
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) | NW 4 | NW 4 | WNW 9 | NW 5 | NNW 6 | NW 6 | NW 5 | NW 5 | NW 5 | NW 5 | NW 5 | NNW 6 | NNW 5 | NW 9 | NW 7 | NNW 7 | N 7 | NNW 7 | NNW 6 | N 6 | NNW 6 |
Wave Graph | |||||||||||||||||||||
11 | 11 | 8 | 13 | 20 | 15 | 17 | 23 | 16 | 13 | 7 | 15 | 11 | 20 | 21 | 108 | 43 | 143 | 68 | 51 | 50 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross-on | on | on | cross-on | cross-on | on | cross-on | glassy | on | cross | cross-on | cross-on | cross | on | cross-on | cross | cross-on | cross-on | cross |
High Tide | 6:12PM4.09m | 6:42AM3.77m | 6:59PM4.11m | 7:28AM3.70m | 7:45PM4.02m | 8:13AM3.57m | 8:30PM3.83m | 8:57AM3.39m | 9:15PM3.56m | 9:43AM3.19m | 10:03PM3.26m | 10:31AM2.99m | 10:55PM2.98m | ||||||||
Low Tide | 11:49AM0.14m | 00:22AM-0.09m | 12:35PM0.09m | 1:09AM-0.07m | 1:21PM0.14m | 1:55AM0.06m | 2:06PM0.27m | 2:40AM0.26m | 2:52PM0.47m | 3:25AM0.51m | 3:40PM0.70m | 4:12AM0.78m | 4:32PM0.94m | ||||||||
6:39 | — | — | 6:39 | — | — | 6:39 | — | — | 6:41 | — | — | 6:41 | — | — | 6:43 | — | — | 6:43 | — | — | |
— | — | 9:45 | — | — | 9:44 | — | — | 9:44 | — | — | 9:43 | — | — | 9:42 | — | — | 9:40 | — | — | 9:39 | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 22 | 23 | 22 | 21 | 23 | 22 | 21 | 22 | 21 | 21 | 23 | 22 | 21 | 23 | 23 | 22 | 24 | 23 | 22 | 24 | 23 |
Feels °C | 22 | 24 | 23 | 22 | 24 | 22 | 21 | 22 | 22 | 23 | 23 | 23 | 22 | 24 | 24 | 23 | 24 | 23 | 21 | 25 | 23 |
Swell 1 Height (m) Direction Period (s) | WNW 10 | NW 4 | WNW 9 | NW 5 | NNW 6 | NW 6 | WNW 9 | WNW 9 | NW 5 | NW 5 | NW 5 | NNW 6 | NNW 5 | NW 5 | NW 7 | NNW 7 | N 7 | NNW 7 | NNW 6 | N 6 | NNW 6 |
10 | 11 | 8 | 13 | 20 | 15 | 8 | 8 | 16 | 13 | 6 | 15 | 11 | 6 | 21 | 108 | 43 | 143 | 68 | 51 | 50 | |
Swell 2 Height (m) Direction Period (s) | W 7 | WNW 10 | NW 9 | WNW 9 | WNW 10 | WNW 9 | — | — | WNW 8 | WNW 8 | WNW 8 | WNW 9 | WNW 8 | NW 9 | NW 8 | W 13 | NNW 8 | NW 12 | WNW 11 | WNW 11 | WNW 10 |
1 | 9 | 3 | 8 | 9 | 8 | — | — | 7 | 7 | 7 | 7 | 7 | 20 | 17 | 3 | 39 | 6 | 12 | 12 | 10 | |
Swell 3 Height (m) Direction Period (s) | NW 7 | W 7 | N 6 | — | — | — | — | — | — | — | — | NW 11 | NNW 10 | — | — | — | — | — | — | — | — |
2 | 1 | 1 | — | — | — | — | — | — | — | — | 4 | 10 | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | NW 4 | — | NW 4 | — | — | — | NW 5 | NW 5 | — | — | — | — | — | — | — | — | — | — | — | — | — |
11 | — | 5 | — | — | — | 17 | 23 | — | — | — | — | — | — | — | — | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 490 | 490 | 526 | 530 | 623 | 791 | 834 | 802 | 711 | 1146 | 620 | 91 | 543 | 619 | 31 | 56 | 110 | 12 | 44 | 87 | 17 |
Best forecast wave conditions in La Cote Basque | |||||||||||||||||||||
Best forecast wave conditions in France | |||||||||||||||||||||
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Information about the Guethary - Les Alcyons/Avalanche Surf forecast
The above surf forecast table for Guethary - Les Alcyons/Avalanche provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Guethary - Les Alcyons/Avalanche can be found by selecting the local surf guide option on the grey menu. Our Guethary - Les Alcyons/Avalanche 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 (Guethary - Les Alcyons/Avalanche) 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 Guethary - Les Alcyons/Avalanche 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.
Guethary - Les Alcyons/Avalanche is 9 km (6 miles) from Biarritz. If you plan a holiday in La Cote Basque, look for hotels and other accommodation in Biarritz. Biarritz has rooms for a wide range of budgets as well as car hire and transport links.










