September, October, November & December is rainy season in Costa Rica but usually the weather is clear in the morning with an hour or so of rain in the afternoon & clear skies at night.
Arenal photos above: December 15, '05 @ 2h24 am, 2h59 am & 3h23 am (full moon). The volcano was very active tonight with lava flowing down every 2 minutes, large & spectacular flows on several different paths, all on the west side. The full moon helps a lot for taking night shots. See our Calendar of sunrises, sunsets and moon phases for Arenal Costa Rica (opens in a separate window)
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