The Intertropical Convergence Zone (ITCZ) has positioned itself directly over Costa Rica this Thursday, bringing with it a rainy afternoon and evening. Thanks to Tropical Wave #9 passing through, we can expect these storms and rain to continue well into the night across the Pacific, Northern Zone, Central Valley, and Caribbean Mountains.
After today, the ITCZ should gradually shift northward across Central America, leading to more isolated rainfall patterns for Costa Rica. But don’t get too comfortable because, as we mentioned in the last forecast, Tropical Wave #10 arrives this Saturday. This will bring another round of strengthened afternoon rains (mornings could be completely fine).
Starting Sunday, things get interesting. Trade winds pick up in the Caribbean Basin, Saharan dust particles drift into the region, and atmospheric humidity decreases. This combination should reduce rainfall in the Pacific and Central Valley regions while Caribbean and Northern Zone shift to a morning and evening rain pattern instead of the typical afternoon storms.
Mornings: Partly cloudy skies across the country provide good windows for early activities and travel. Some coastal areas might catch isolated early showers, especially as the tropical waves pass through.
Afternoons: Classic rainy season action with cloudy skies and thunderstorms developing in the Pacific, Central Valley, and Northern Zone. Expect the most intense activity Thursday through Saturday. The Caribbean stays partly cloudy with mountain showers.
Evenings: Cloud cover and rain dominate the Pacific and Northern Zone, especially Thursday-Saturday. The Central Valley sees scattered evening showers, while the Caribbean experiences ongoing rain early in the week before the pattern shifts.
High: 31° (87.8°) | Low: 15° (59°)
High: 34° (93.2°) | Low: 20° (68°)
High: 33° (91.4°) | Low: 15° (59°)
High: 33° (91.4°) | Low: 15° (59°)
High: 32° (89.6°) | Low: 20° (68°)
High: 34° (93.2°) | Low: 17° (62.6°)
Thursday-Saturday: These are your most active weather days with two tropical waves moving through. Perfect time for indoor cultural experiences, museums, coffee tours, or spa days. If you’re heading outdoors, stick to morning hours with flexible backup plans.
Sunday onward: As trade winds strengthen and humidity drops, the Pacific and Central Valley become much more manageable for outdoor activities. The Caribbean and Northern Zone switch to a unique morning/evening rain pattern, making midday the sweet spot for activities. Look for a new forecast on Monday with more details.
*This forecast is based on the weekly outlook shared by Costa Rica’s National Meteorological Institute (IMN).
