Arenal Volcano - Costa Rica?

Question

What is the best time of year to get really good photographs of this volcano, and what time of day is it best viewed?

Answer 1

any day that you are in luck. mostly in january that we don't get much rain

Answer 2

Late November and early December, toward the end of the rainy season (rains frequently but not daily).  The air is especially clear, the backgrounds have clean color, not yet covered with dust as is the case after January.  The plants are still colorful.

There is not single best time of day.  Early in the morning  gives dramatic back lighting.  Late dusk ives spectacular sunsets.  Midday gives strong light for detailed photos, depends on what you are trying to get.