There really isn't one single best time to be in Costa Rica, all of the weather seasons in Guanacaste offer somthing special.  Different seasons offer many different positive experiences from non stop sunshine to tropic green rolling mountains.  I would say that it really depends on what kind of lifestyle you're looking for.  That will help determine if you would prefer to live here part time, or on a more full time basis.

Guanacaste is the northwest province of the country and is the warmest and driest of all of Costa Rica.  Guanacaste is completely dry from mid-November through May.  This also represents the busiest time in places such as Playas del Coco, Playa Panama, and Playa Hermosa.  Many tourists flee the cold weather of the U.S. and Canada for the warm dry beaches during this time.  During this time the dance clubs are the busiest, restaurants fullist, and streets most lively.  Many people really enjoy the atmosphere of these latin beaches during this time, and who could blame them.... It's really a blast!

From mid May through early September the temperatures are a little cooler and there is an afternoon sprinkle.  This light rain could last anywhere from 15 minutes to an hour and a half.  During this season everything is green and lively.  There are still many tourist, but not as many as during the dry season.  I admit that this type of season is possibly the best for many people as there are not as many crowds and the temparature is a little cooler.  Tourist may also notice that prices are at slightly better rates during the green season as well.

There is one last season that is truly a rainy season.  This is from late September through October.  For anywhere from 4-6 weeks it will rain nearly everyday for extended periods at a time.  While there are still locals and tourist alike who will be around town, there are much less in numbers during this time.

The Guanacaste region is truly the place to be whether it is for a week, a month, or an entire season.  Take time to identify what you desire the most, and line up the season to coincide with your desires.  There is never a "bad" time to come to Playas del Coco, Playa Hermosa or Playa Panama.

Pura Vida!