Arenal enjoys a fairly pleasant mountain environment with secondary rainforest characteristics. The volcano is obscured by cloud coverage 50% of the time, regardless of the season.
Mid-December to April is the dry season, though the occasional shower does occasionally happen during this time. May through November is the “green” season when daily afternoon showers are the norm. October is typically the rainiest month of the year.
Expect temps in the 70s-90s, depending on cloud coverage on any given day. Evenings and early morning can be a bit cooler, dipping into the ’60s. Bring a sweater or light jacket!
