Rain is likely to reach your lantern parade tonight. The National Meteorological Institute (IMN) expects downpours with thunderstorms across the Central and South Pacific through the afternoon, and rain over the Caribbean and Northern Zone after dark. If you are heading out with children and paper faroles, plan for wet pavement and know where you can take cover.
The afternoon storms will form over the mountains first and push toward the coast as the day goes on, according to IMN meteorologist Adriana Mora. That sequence matters for timing. Inland in the Central and South Pacific, the rain arrives earlier. At the beach, it tends to reach you later, closer to the hour most parades step off.
In the Central Valley, expect cloud cover ranging from partial to complete, with occasional rain in the surrounding areas. San Jose, Heredia, Alajuela and Cartago all sit in that band, and Cartago has a presidential ceremony and the arrival of the Independence Torch on top of its parade.
The North Pacific is the exception tonight as moderate winds are keeping conditions there less favorable for rain, so Guanacaste has the best odds of a dry evening. The southern end of the Nicoya Peninsula is the caveat, where Mora said isolated downpours with thunderstorms cannot be ruled out.
The Caribbean and Northern area get their turn later. Cloud cover builds through the afternoon there and the rain arrives mainly at night, carrying into the early hours of Tuesday. Along the Caribbean coast, in Puerto Viejo, and across the San Carlos plains, the parade window and the wettest window overlap.
The reason is the trade winds. Mora said the winds over the Caribbean basin are running at moderate to accelerated speeds, which is dragging the heaviest atmospheric moisture over the country. That is the engine behind the instability, and it is why the Caribbean side gets its rain overnight rather than in the afternoon.
This morning looked nothing like that as conditions were mostly clear to partly cloudy across much of the country, with only weak, scattered rain over the Caribbean and Northern Zone. A calm morning is not a forecast for the evening and today is a good example of why.
IMN has not published accumulation figures for tonight, so treat the outlook as directional rather than precise. Lightning is the part worth respecting. An afternoon thunderstorm in the Pacific highlands is a reason to move indoors, not a reason to wait it out under a tree or a metal roof.
Tomorrow is Independence Day and school parades run through the morning in town centers nationwide. Overnight rain on the Caribbean side and in the Northern Zone can leave wet, slick streets for those parades even where the sky clears by sunrise. Faroles are paper and candlelight, and September is one of the wettest months of the year across most of Costa Rica. A plastic cover for the lantern and leaving a few minutes earlier than planned are usually what separates a soaked evening from a good one.
