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Surf Forecasts:

Avellanas Rivermouth surfForecast / Guanacaste / Costa Rica

information circle12 Day Weather and Surf, issued 11 am Saturday 18 Oct 2025 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
28.3° C
 (Which is slightly warmer than usual)

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 Sunday (Oct 19) at 3AM. The primary swell is predicted to be 1.1m and 15s period with a secondary swell of 0.6m and 7s. 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 1.2m 15s and forecast to arrive on Saturday (Oct 18) at 6PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 5s period and expected on Tuesday (Oct 21) at 9PM.

Wave TypeTime (CST) & Date Wave Height & Period
Next good surf (1 star+) 3AM (Sun 19th Oct)3.5ft (1.1m) 15s
Best Surf 3AM (Sun 19th Oct)3.5ft (1.1m) 15s
Most Powerful 6PM (Sat 18th Oct)4ft (1.2m) 15s

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

Updates in  hr  min  s Forecast update imminent 
12 DaysHourly
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Short Range Forecast Heavy rain (total 33mm), heaviest during Mon night. Warm (max 27°C on Sat morning, min 24°C on Mon night). Wind will be generally light.

Days 3-6 Weather Summary Heavy rain (total 23mm), heaviest during Tue afternoon. Warm (max 27°C on Tue morning, min 24°C on Wed afternoon). Wind will be generally light.

Saturday
18
Sunday
19
Monday
20
Tuesday
21
Wednesday
22
Thursday
23
Friday
24
AMPMNightAMPMNightAMPMNightAMPMNightAMPMNightAMPMNightAMPMNight
Rating
(10 max)
2
2
2
3
3
2
2
2
0
1
1
1
1
1
0
0
1
2
2
2
2
Swell
Height Map
See all maps
Wave Height (m) & direction (?)
1.2
SSW
1.2
SW
1.2
SW
1.1
SW
1.1
SW
0.9
SW
0.7
SW
0.7
SW
0.9
SW
0.9
SW
0.9
SW
0.8
SW
0.6
SW
0.8
SW
0.8
SW
0.8
SW
0.8
SW
0.8
SW
0.6
SW
0.6
SW
0.6
SW
Period(s) (?)161515151414161614141414161616151414141313
Wave
Graph
(?)Metric surfscale
Energy kJ (?)649666631489476350239236284293297241203302291255251245147142109
Wind
(km/h)
10
SSE
15
SSW
5
SSE
5
S
15
WSW
0
NW
5
WNW
15
W
15
NE
10
ENE
15
NNE
10
NNE
20
NNW
20
NNW
15
NNE
15
NNE
15
N
5
N
5
SSE
10
W
0
SSE
Wind State (?)
onshore
cross-onshore
cross-shore
cross-offshore
offshore
glassy
cross-
on		cross-
off		cross-
on		glasscross-
off		glassglassoffcross-
on		cross-
on		cross-
on		cross-
on		cross-
off		cross-
off		cross-
on		cross-
on		cross-
off		glassglassoffglass
High Tide
/ height (m)
12:35PM
2.05
12:59AM
2.23
1:23PM
2.11
1:39AM
2.31
2:04PM
2.16
2:15AM
2.37
2:41PM
2.20
2:50AM
2.41
3:17PM
2.22
3:25AM
2.41
3:52PM
2.21
4:00AM
2.38
4:28PM
2.16
Low Tide
/ height (m)
6:42PM
0.53
7:16AM
0.47
7:26PM
0.48
7:57AM
0.38
8:04PM
0.44
8:34AM
0.30
8:40PM
0.41
9:10AM
0.25
9:16PM
0.40
9:45AM
0.23
9:50PM
0.41
10:20AM
0.26
10:25PM
0.45
Saturday
18
Sunday
19
Monday
20
Tuesday
21
Wednesday
22
Thursday
23
Friday
24
Sunrise5:31--5:31--5:31--5:31--5:31--5:31--5:31--
Sunset-5:23--5:23--5:22--5:22--5:22--5:22--5:22-
thunderstorm
thunderstorm
rain showers
rain showers
thunderstorm
thunderstorm
rain showers
thunderstorm
thunderstorm
thunderstorm
thunderstorm
rain showers
thunderstorm
rain showers
rain showers
rain showers
rain showers
rain showers
thunderstorm
thunderstorm
rain showers
Rain (mm)
3113451312341224124325
Temp. °C272726272726272726272625262524272725272725
Feels °C (?)292930313031323029302828272626292928303030
  • Map Icons:
  • Break
  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
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Eyeball surf reportRecent Eyeball Surf Reports for Guanacaste

  1. weather stationWind Update Calm condsitions have become offshore at Avellanas Rivermouth (light winds from the W at Liberia/Tomas Guardia Airport 51 km from Avellanas Rivermouth). 0.9m 16s long period groundswell from the SW with a 0.7m 7s swell from the WSW and a 0.5m 6s windswell from the S. 3 swells combining to make bigger set waves.

    1 hour 35 minutes ago Avellanas Rivermouth
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The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Avellanas Rivermouth surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.

View detailed surf forecast for Avellanas Rivermouth at:
surf-forecast.com

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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