Guethary - Les Alcyons/Avalanche Surf Break

Lat Long: 43.43° N 1.62° W

Guethary - Les Alcyons/Avalanche Surf Forecast and Surf Report

Issued: 7 am 10 Aug 2026 (local time)

Forecast update in  hr  min

Today's Guethary - Les Alcyons/Avalanche sea temperature is
24.1° C
2.3° 

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 10 Aug 2026:

  • Most powerful swell: Sunday 16 Aug, 8PM (local time) - 3.5ft (1.1m), 7s period, NW swell with 140 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 1.1m 7s and forecast to arrive on Sunday (Aug 16) at 8PM. Winds are predicted to be onshore at the time the swell arrives.

Wave TypeTime (CEST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful 8PM (Sun 16th Aug)3.5ft (1.1m) 7s

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


The Lowdown

Alright crew, Rusty here. Let’s talk about the surf.

The water is warm, sitting at about 75°F, which is a few degrees warmer than usual for this time of year—comfortable without a full wetsuit.

We’ve got a real dry spell on our hands. From Monday the 10th through Saturday the 16th, it’s mostly flat or tiny, with weak onshore winds. The swell is small, like 1 to 2 feet, and the wind is mostly onshore, so the ocean is messy and uninviting. The energy is weak (combined energy around 57 to 129), and the period is short, so no real power or shape.

Sunday the 16th morning gives us a glassy window with 3 feet of weak NW swell, but it’s still not enough to get excited about. You’ll be waiting.

The first real sign of life comes on Thursday the 20th. The morning has a light cross-off breeze from the ENE, and the swell bumps up to 2 feet from the NW with a 10-second period. The combined energy hits 129 (moderate), and the wave comment says “surfable but ordinary.” After a week of nothing, this is a welcome change.

The standout is Monday the 24th. The morning swell jumps to 5 feet from the NW, 10-second period, and the combined energy is a massive 520 (very strong). The wind is onshore from the NNW, so it’s not clean, but for experts on a reef break like Guethary - Les Alcyons/Avalanche, that’s a serious amount of water moving. The afternoon is a bit smaller at 5 feet, but still onshore. This is big, powerful surf—only for the experienced.

Tuesday the 25th morning looks more user-friendly: glassy conditions with a north wind, 3 feet of NW swell, and combined energy at 196. That’s a fun, clean wave, though not the biggest.

So, the first week is a wash, then things pick up from the 20th. The 24th has the most power, but the wind is a problem. The 25th morning might be the best bet for a clean, manageable session.

Rusty out.

Short Range Forecast

Mostly dry. Warm (max 29°C on Wed afternoon, min 19°C on Tue morning). Wind will be generally light.

Days 4-6 Weather Summary

Mostly dry. Warm (max 26°C on Thu afternoon, min 20°C on Thu night). Wind will be generally light.

Monday
10
Tuesday
11
Wednesday
12
Thursday
13
Friday
14
Saturday
15
Sunday
16
AM
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
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.7
NW
9
0.7
NW
9
0.7
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
0.5
W
10
0.4
WNW
10
0.6
WNW
11
0.6
WNW
10
0.6
WNW
10
0.6
WNW
9
0.6
WNW
9
0.9
NW
7
0.8
NW
7
0.8
NW
8
1.1
NW
8
0.9
NW
7
Wave Graph
Metric surfscale
Energy kJ
81
81
81
76
59
55
57
34
28
50
32
93
77
72
65
53
82
54
90
125
69
Wind (km/h)
10
WNW
10
NW
5
WSW
5
NW
15
NNW
10
SW
5
NNE
15
N
15
WSW
5
WNW
15
WNW
15
WSW
10
WNW
10
NW
15
W
5
NW
10
WNW
10
WSW
5
W
10
NW
5
WSW
Wind State
cross-on
on
glassy
glassy
on
cross
glassy
cross-on
cross
on
on
cross-on
on
on
cross-on
on
on
cross-on
glassy
on
cross
High Tide
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
7:40AM3.68m
7:56PM3.82m
Low Tide
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
1:36PM0.16m
2:03AM0.24m
part cloud
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
part cloud
part cloud
clear
clear
part cloud
clear
<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
7:11
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
9:16
9:15
9:14
9:13
9:12
9:09
9:08
 mm
Temp °C
22
23
23
22
25
23
25
29
25
24
26
23
22
23
22
22
24
22
23
25
23
Feels °C
24
25
25
24
27
25
28
30
28
26
28
25
24
24
23
24
26
23
26
27
25
  • Map Icons:
  • Break
  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
Map placeholder
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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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