Costa Rica Weather August
for other months visit here ;
http://costa-rica-guide.com/travel/index.php?option=com_content&task=view&id=500&Itemid=691

The majority of the rain falls in the afternoon or overnight in Costa Rica. The hot August sun evaporates moisture from the sea and rainforest canopy creating a layer of warm moist air that rises as the day progresses. As the air rises it expands and cools causing the water to condense out forming clouds. Later in the day as the temperatures fall the air can hold even less water and some of it falls as rain.xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

August is in the middle of the rainy season but many years there is a lull in the rains (especially in Guanacaste) usually starting in July and ending in August. Costa Ricans call this little dry season veranillo (how does it happen?) and if you're lucky you won't need your umbrella at all on a visit to the northwest.

The Caribbean side is solidly in the rainy season weather pattern with some rain nearly every evening or overnight.

The beaches and lowlands have high temperatures in the low nineties and low temperatures in the upper seventies or low eighties. A week or two of temperatures in the mid nineties is possible at low elevations and especially on the Nicoya coast during August. The higher you go the more it cools off so if you're looking for some relief head to the mountains. Temperatures around the central valley are usually in the upper seventies and low eighties this time of year.