Guethary - Les Alcyons/Avalanche Surf Break

Lat Long: 43.43° N 1.62° W

Guethary - Les Alcyons/Avalanche Surf Forecast and Surf Report

Issued: 1 pm 09 Aug 2026 (local time)

Forecast update in  hr  min

Today's Guethary - Les Alcyons/Avalanche sea temperature is
24.2° C
2.5° 

Guethary - Les Alcyons/Avalanche surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Guethary - Les Alcyons/Avalanche surf forecast from 9 Aug 2026:

  • Best quality surf: Monday 10 Aug, 11PM (local time) - 2.5ft (0.8m), 10s period, NW swell with glassy winds.
  • Most powerful swell: Monday 10 Aug, 11PM (local time) - 2.5ft (0.8m), 10s period, NW swell with 110 kJ wave energy.
  • Next surfable swell (1★+): Monday 10 Aug, 11PM (local time) - 2.5ft (0.8m), 10s period with NW swell.

Best Forecast Surf Conditions for Guethary - Les Alcyons/Avalanche this week:

The surf forecast for Guethary - Les Alcyons/Avalanche over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Monday (Aug 10) at 11PM. The primary swell is predicted to be 0.8m and 10s period. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 0.8m 10s and forecast to arrive on Monday (Aug 10) at 11PM. Winds are predicted to be glassy at the time the swell arrives.

Wave TypeTime (CEST) & Date Wave Height & Period
Next good surf (1 star+)11PM (Mon 10th Aug)2.5ft (0.8m) 10s
Best Surf11PM (Mon 10th Aug)2.5ft (0.8m) 10s
Most Powerful11PM (Mon 10th Aug)2.5ft (0.8m) 10s

Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.


The Lowdown

Alright, Rusty here. Let's have a look at what's on the cards for the coming weeks.

First thing you need to know - the water is running much warmer than normal for this time of year, sitting at 76°F at Guethary - Les Alcyons/Avalanche. That's a solid 5°F above average, so you can leave the thick spring suit at home.

Now, I'm not gonna sugarcoat it. The next week and a half is basically a write-off. We've got a whole lot of nothing and a whole lot of messy. From the 9th of August right through to the 21st, it's a grim stretch of tiny, weak swell and poor conditions. The swell is barely scraping 3ft, and the energy is threadbare, often well under 100 (119 at its peak, dropping to a measly 16). The wind is a constant problem - mostly cross-on, onshore, or just generally chopping things up. You'll get the odd glassy morning on the 11th, 12th, and 18th, but with the swell so small and the period short (8-10 seconds), it's just not worth the paddle. The wave comment says it all: "poor surf conditions" day after day.

Then, we finally get a flicker of something. On Saturday the 22nd of August, the morning is looking like a bit of a wildcard. The swell is still small at 2ft, but it's got a bit more push with a period of 11 seconds, and the combined energy jumps up to 122 (moderate). The real kicker is the wind: a clean, cross-off breeze from the ENE. That'll put a nice face on the wave. It's "surfable waves but very ordinary conditions" according to the report, but a clean 2ft on a reef break like this can be a lot more fun than the numbers suggest. Just be aware that crowds are often a problem here, so you won't be alone.

Sunday the 23rd of August morning is another one to keep an eye on. Glassy conditions with a 2ft, 9-second NW swell and energy at 118. Again, "surfable but very ordinary", but glassy is glassy.

The one true standout that's worth circling on the calendar is Monday the 24th of August. The morning session is where it's at. The swell is pushing up to 3ft, coming from the NW, and the combined energy hits a solid 228 (moderate). The wind is light and cross-off from the ENE, giving us clean conditions. The report actually says "expect good surf conditions" with a score of 2 out of 10. For a stretch that's been all zeros, that's a big deal. That 9-second period is a decent groundswell, and on a reef like Les Alcyons, it should line up nicely. The afternoon gets ruined by a cross-on breeze, so make it a dawn patrol mission.

So, to sum it up: the first two weeks are a bust. The 22nd and 23rd are worth a look for the clean windows, but the real call is the morning of the 24th of August.

Rusty.

Short Range Forecast

Light rain (total 4mm), mostly falling on Sun afternoon. Warm (max 25°C on Tue afternoon, min 19°C on Tue morning). Wind will be generally light.

Days 5-7 Weather Summary

Some drizzle, heaviest during Fri night. Warm (max 29°C on Wed afternoon, min 20°C on Thu night). Wind will be generally light.

Sun
9
Monday
10
Tuesday
11
Wednesday
12
Thursday
13
Friday
14
Saturday
15
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.8
NW
10
0.7
NW
10
0.7
NW
9
0.7
NW
9
0.8
NW
9
0.7
NW
9
0.6
NW
9
0.6
NW
8
0.6
NW
8
0.4
WNW
10
0.4
WNW
9
0.4
WNW
10
0.5
W
10
0.6
WNW
11
0.6
WNW
10
0.6
WNW
10
0.5
WNW
9
0.5
WNW
9
0.8
NW
5
0.6
WNW
9
Wave Graph
Metric surfscale
Energy kJ
117
90
81
81
99
76
59
55
57
34
28
31
48
95
78
74
47
45
40
49
Wind (km/h)
10
W
10
WSW
5
WNW
10
NNW
5
SW
5
NNW
15
NNW
10
WSW
5
NNE
15
N
10
SW
5
WNW
15
WNW
15
WSW
10
WNW
10
WNW
15
W
10
WNW
15
NW
5
WNW
Wind State
cross-on
cross-on
cross-on
on
glassy
glassy
on
cross
glassy
cross-on
cross
on
on
cross-on
cross-on
on
cross-on
on
on
cross-on
High Tide
2:25PM3.17m
3:06AM3.18m
3:31PM3.46m
4:06AM3.43m
4:25PM3.77m
4:56AM3.64m
5:13PM4.01m
5:41AM3.78m
5:57PM4.15m
6:23AM3.83m
6:38PM4.16m
7:02AM3.79m
7:18PM4.05m
Low Tide
8:38PM0.72m
9:04AM0.74m
9:41PM0.43m
10:01AM0.47m
10:34PM0.15m
10:50AM0.23m
11:22PM-0.05m
11:34AM0.07m
00:05AM-0.14m
12:16PM-0.01m
00:46AM-0.12m
12:56PM0.03m
1:25AM0.01m
rain showers
thunderstorm
part cloud
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
part cloud
clear
rain showers
part cloud
part cloud
rain showers
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
7:05
7:05
7:07
7:07
7:09
7:09
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
9:19
9:16
9:15
9:14
9:13
9:12
9:09
 mm
1
3
1
5
Temp °C
24
22
21
24
23
22
25
23
24
29
26
24
26
23
22
23
22
22
22
21
Feels °C
24
23
23
26
25
25
26
25
27
30
29
26
28
24
23
24
22
24
22
23
  • Map Icons:
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  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
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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.

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