My friend and extraordinary all-round beach athlete Todd Clark was kind to turn me on to this site:
http://www.windguru.cz/int/index.php?sc=4877
It gives accurate, several times per day forecasts for wind, waves, and weather. Great information to have when planning one's activities!
And here is another great one for surfing conditions which includes tides:
http://magicseaweed.com/Tamarindo-Surf-Report/444/
Enjoy!