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Surf Forecasts:

Avellanas Rivermouth surfForecast / Guanacaste / Costa Rica

information circle12 Day Weather and Surf, issued 11 pm Tuesday 06 Jan 2026 CST
Forecast update in hr  min  s Forecast update imminent
Avellanas Rivermouth surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.
Today's Avellanas Rivermouth sea temperature is
28.4° C
 (Which is 1.5°C warmer than normal for this time of year)

Best Forecast Surf Conditions for Avellanas Rivermouth this week:

The surf forecast for Avellanas Rivermouth over the next 12 days: The first swell (rated 1 star or higher) is forecast to arrive on Wednesday (Jan 07) at 12PM. The primary swell is predicted to be 0.4m and 12s period with a secondary swell of 0.5m and 6s. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Avellanas Rivermouth in the next 12 days are 0.8m 12s and forecast to arrive on Saturday (Jan 10) at 3AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.6m 4s period and expected on Friday (Jan 09) at 9PM.

Wave TypeTime (CST) & Date Wave Height & Period
Next good surf (1 star+)12PM (Wed 7th Jan)1.5ft (0.4m) 12s
Best Surf12PM (Wed 7th Jan)1.5ft (0.4m) 12s
Most Powerful 3AM (Sat 10th Jan)2.5ft (0.8m) 12s

Table - best surf conditions forecast for Avellanas Rivermouth over the next 12 days.

Updates in  hr  min  s Forecast update imminent 
12 DaysHourly
Print Table

Short Range Forecast Mostly dry. Warm (max 30°C on Wed morning, min 22°C on Tue night). Wind will be generally light.

Days 3-6 Weather Summary Mostly dry. Warm (max 31°C on Sun afternoon, min 22°C on Sun night). Winds increasing (light winds from the SSE on Sat afternoon, fresh winds from the NE by Mon morning).

Wednesday
07
Thursday
08
Friday
09
Saturday
10
Sunday
11
Monday
12
Tue
13
NightAMPMNightAMPMNightAMPMNightAMPMNightAMPMNightAMPMNightAMPM
Rating
(10 max)
0
0
1
0
0
1
0
0
1
0
0
1
0
0
0
0
0
0
0
0
1
Swell
Height Map
See all maps
Wave Height (m) & direction (?)
0.6
SSW
0.5
SW
0.4
SSW
0.4
SW
0.5
SW
0.5
SW
0.6
SW
0.6
SW
0.6
SW
0.8
SW
0.6
SW
0.6
SW
0.7
SW
0.6
SSW
0.6
SW
0.5
SW
1.1
NNE
0.9
NNE
0.6
WNW
0.7
WNW
0.7
WNW
Period(s) (?)1212121414131312121213131212121255111110
Wave
Graph
(?)Metric surfscale
Energy kJ (?)98715672898713812293178128132152941146859468210986
Wind
(km/h)
20
ENE
20
ENE
10
W
20
ENE
20
ENE
10
WSW
10
E
15
NE
10
SW
15
ENE
20
ENE
5
SSW
20
ENE
25
NE
30
NE
20
ENE
25
NE
30
NE
20
ENE
20
ENE
5
NNE
Wind State (?)
onshore
cross-onshore
cross-shore
cross-offshore
offshore
glassy
oncross-
on		offoncross-
on		cross-
off		oncross-
on		cross-
off		oncross-
on		cross-
off		cross-
on		cross-
on		cross-
on		cross-
on		cross-
on		cross-
on		oncross-
on		glass
High Tide
/ height (m)
5:17AM
2.49
5:51PM
2.49
6:03AM
2.36
6:37PM
2.43
6:50AM
2.21
7:22PM
2.33
7:38AM
2.05
8:08PM
2.22
8:29AM
1.91
8:57PM
2.12
9:24AM
1.79
9:50PM
2.04
10:26AM
1.72
Low Tide
/ height (m)
11:10PM
0.24
11:33AM
0.07
12:00AM
0.32
12:17PM
0.19
12:49AM
0.42
1:01PM
0.34
1:39AM
0.52
1:46PM
0.49
2:30AM
0.61
2:33PM
0.63
3:26AM
0.68
3:25PM
0.74
4:26AM
0.72
4:23PM
0.80
Wednesday
07
Thursday
08
Friday
09
Saturday
10
Sunday
11
Monday
12
Tue
13
Sunrise-6:01--6:03--6:03--6:03--6:03--6:03--6:03-
Sunset--5:36--5:36--5:37--5:37--5:37--5:37--5:38
clear
clear
part cloud
clear
clear
part cloud
clear
clear
part cloud
clear
clear
part cloud
clear
clear
part cloud
part cloud
clear
part cloud
part cloud
clear
part cloud
Rain (mm)
---------------------
Temp. °C263029252928263028263029263031262930262930
Feels °C (?)283230263230293130273231282828242627242933
  • 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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View detailed surf forecast for Avellanas Rivermouth at:
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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 12 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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