Avellanas Rivermouth Surf Break

Lat Long: 10.24° N 85.84° W

Avellanas Rivermouth Surf Forecast and Surf Report

Issued: 5 pm 09 Jul 2026 (local time)

Forecast update in  hr  min

Today's Avellanas Rivermouth sea temperature is
30.0° C
1.8° 

Avellanas Rivermouth surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Avellanas Rivermouth surf forecast from 10 Jul 2026:

  • Best quality surf: Saturday 11 Jul, 6AM (local time) - 3ft (0.9m), 15s period, SSW swell with glassy winds.
  • Most powerful swell: Friday 10 Jul, 9PM (local time) - 3ft (0.9m), 15s period, SSW swell with 403 kJ wave energy.
  • Next surfable swell (1★+): Friday 10 Jul, 3PM (local time) - 2.5ft (0.8m), 15s period with SSW swell.

Best Forecast Surf Conditions for Avellanas Rivermouth this week:

The surf forecast for Avellanas Rivermouth over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Friday (Jul 10) at 3PM. The primary swell is predicted to be 0.8m and 15s period with a secondary swell of 0.7m and 9s. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Avellanas Rivermouth in the next 16 days are 0.9m 15s and forecast to arrive on Friday (Jul 10) at 9PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.5m 5s period and expected on Thursday (Jul 16) at 12PM.

Wave TypeTime (CST) & Date Wave Height & Period
Next good surf (1 star+) 3PM (Fri 10th Jul)2.5ft (0.8m) 15s
Best Surf 6AM (Sat 11th Jul)3ft (0.9m) 15s
Most Powerful 9PM (Fri 10th Jul)3ft (0.9m) 15s

Table - best surf conditions forecast for Avellanas Rivermouth over the next 16 days.


Alright folks, Rusty here. Let’s have a look at what’s on the menu for the next couple of weeks.

The first real window of opportunity here is a bit of a slow burn, but we’ve got some solid chances, especially for the crew who like cleaner conditions. The swell is hanging around the 3 ft mark from the SSW for the first few days, but the wind is the main issue. That cross-onshore breeze is making things messy, so don’t get too excited about Thursday or Friday mornings.

The first real standout comes on the morning of Friday, July 11th. Avellanas Rivermouth is looking at a 3 ft SSW groundswell with a long 15-second period, and the wind is going glassy. That’s a beautiful combination. The water is a touch warmer than normal at 86°, so it’s a nice comfortable session. The combined wave energy is moderate at 516, but the clean conditions will make it feel punchy. This is a sandbar setup, so it can be a bit inconsistent, but when it’s on, it’s on. This is the pick of the first week.

The following Saturday morning, July 12th, also looks promising with similar 3 ft SSW swell and glassy conditions again. The energy is a bit stronger at 594. It’s a solid choice for a clean weekend session.

After that, the wind turns a bit fluky, with some cross-onshore days and a few cleaner windows in the afternoons. The swell drops off a touch, but we get a few slots with offshore winds, like the afternoon of Wednesday, July 16th, with a 2 ft SSW swell and a clean offshore breeze. Not a standout, but a good session if you’re keen.

Then we get a real wildcard. On the morning of Tuesday, July 21st, the swell jumps to 8 ft from the SSW, but it’s a short period of 9 seconds. That’s a lot of water moving in a hurry, and the combined energy is a massive 2040, which is very strong. The wind is cross-onshore, so it’s going to be a messy, powerful beast. This is strictly for experts. However, the afternoon of that same day cleans right up with a 6 ft SSW swell, an 8-second period, and a clean cross-offshore breeze. The energy is still high at 814, and it’s rated as very good surf. That’s a huge, powerful, clean wave, but still only for strong surfers.

Finally, on Friday, July 24th, we get another clean afternoon with a 4 ft S swell and a clean cross-offshore breeze. It’s a good way to wrap up the period.

Overall, the best bet is the glassy morning of July 11th. The big, clean afternoon of July 21st is a serious session for the experienced crew.

Rusty.

Short Range Forecast

Heavy rain (total 24mm), heaviest during Fri night. Warm (max 33°C on Thu afternoon, min 25°C on Sat night). Wind will be generally light.

Days 5-7 Weather Summary

Moderate rain (total 18mm), heaviest on Sun afternoon. Warm (max 30°C on Mon morning, min 24°C on Sun night). Wind will be generally light.

Thu
9
Friday
10
Saturday
11
Sunday
12
Monday
13
Tuesday
14
Wednesday
15
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
Rating
(10 max)
0
0
0
2
2
3
3
2
1
0
1
0
2
0
0
2
0
0
2
0
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.9
SSW
16
0.9
SW
15
0.9
SSW
15
0.8
SSW
15
0.9
SSW
15
0.9
SSW
15
0.9
SSW
14
0.9
SSW
14
0.9
SW
14
0.9
SW
14
0.6
SW
13
0.7
SW
14
0.6
SSW
14
0.6
S
15
0.6
S
15
0.7
SSW
14
0.6
SW
18
0.7
SSW
13
0.6
SW
16
0.6
SW
16
0.6
S
13
Wave Graph
Metric surfscale
Energy kJ
419
314
382
279
403
372
362
323
297
264
130
200
132
159
155
207
194
181
193
206
125
Wind (km/h)
20
ENE
20
ENE
20
ENE
5
SSE
10
SE
5
E
5
WSW
5
SSE
5
NNE
10
NE
5
ESE
10
NE
10
SW
15
ENE
20
ENE
0
ENE
15
ENE
20
ENE
15
W
10
ENE
15
ENE
Wind State
cross-on
on
cross-on
glassy
cross-on
glassy
glassy
glassy
cross-on
cross-on
cross-on
cross-on
cross-off
on
on
glassy
cross-on
on
off
cross-on
on
High Tide
9:40PM1.91m
10:09AM2.31m
10:47PM1.92m
11:14AM2.36m
11:56PM2.00m
12:19PM2.43m
1:01AM2.12m
1:21PM2.52m
2:01AM2.26m
2:19PM2.59m
2:57AM2.41m
3:13PM2.63m
3:50AM2.52m
Low Tide
3:38PM0.54m
3:40AM0.55m
4:43PM0.48m
4:46AM0.53m
5:49PM0.38m
5:55AM0.47m
6:51PM0.26m
7:00AM0.37m
7:49PM0.14m
8:02AM0.28m
8:43PM0.03m
9:00AM0.20m
9:34PM-0.03m
9:55AM0.16m
part cloud
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thunderstorm
thunderstorm
thunderstorm
thunderstorm
thunderstorm
part cloud
mod rain
light rain
part cloud
thunderstorm
thunderstorm
thunderstorm
thunderstorm
part cloud
part cloud
thunderstorm
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<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:28
5:28
5:28
5:28
5:28
5:28
5:28
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:08
6:08
6:08
6:08
6:08
6:08
6:08
6:08
 mm
3
6
7
6
2
7
4
2
2
1
2
2
Temp °C
33
28
31
31
28
28
28
27
30
29
25
30
29
27
29
29
26
30
28
27
30
Feels °C
35
29
33
36
32
32
32
31
33
32
27
33
32
30
32
34
29
33
31
31
34
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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 Avellanas Rivermouth Surf forecast

The above surf forecast table for Avellanas Rivermouth provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Avellanas Rivermouth can be found by selecting the local surf guide option on the grey menu. Our Avellanas Rivermouth 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 (Avellanas Rivermouth) 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 Avellanas Rivermouth 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.

Avellanas Rivermouth is 44 km (27 miles) from Nicoya. If you plan a holiday in Guanacaste, look for hotels and other accommodation in Nicoya. Nicoya has rooms for a wide range of budgets as well as car hire and transport links.

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