Worst time to visit Costa Rica

The worst month to visit Costa Rica is September

September is the wettest month on the Pacific side. At Liberia, the gateway to the Guanacaste beaches, it averages 346mm of rain with just 8 hours of sun a day. Unlike the early green season, when rain arrives as a predictable afternoon downpour, September and October rain can last all day and through the night. (These figures describe the Pacific north — the Caribbean coast and San José run on different calendars.)

October is a close second at 310mm. Together they form the window that Costa Ricans call the temporales — the weeks when the Pacific tropical-storm influence is strongest, rivers swell, and the gravel roads to Monteverde, Santa Teresa, and the Osa Peninsula become difficult or impassable. A number of remote lodges close entirely for the two months.

Why September and October are genuinely difficult

• Volume of rain. 310–346mm a month at Liberia on the Pacific side, and wet in the Central Valley too. Downpours flood roads in San José and turn unpaved routes to mud.
• Landslides and washouts. The Route 32 highway to the Caribbean and the mountain roads around Monteverde close periodically for slides. Check the Instituto Meteorológico Nacional before driving.
• Seasonal closures. Lodges on the Osa, in Nicoya, and around Drake Bay often close for September and October. Boat services to Tortuguero and Drake Bay are more likely to be cancelled for rough water.
• No volcano views. Arenal spends most of the two months in cloud; the famous cone is rarely visible.

The trade-off: these are the cheapest months of the year, with steep hotel discounts and the whale-watching season on the south Pacific coast at its peak.

The exception that changes the answer: the Caribbean coast

Costa Rica's Caribbean side runs on a different calendar. Puerto Viejo, Cahuita, and Tortuguero are at their driest and sunniest in September and October — while the Pacific drowns. Their wet months are November–December and June–July.

• Puerto Viejo in September: calm sea, clear snorkelling at Cahuita, few visitors
• Tortuguero in September–October: peak green-turtle nesting and hatching season
• Route 32 from San José is the one risk — allow a spare day for closures

If your dates are fixed to September or October, the Caribbean coast is not a compromise — it is the right answer.

If you have to travel to the Pacific side in green season

• Front-load every day. Ziplines, hikes, boat trips, and the Arenal hanging bridges before 11am; rain usually builds from early afternoon.
• Stick to paved routes.Guanacaste beaches, La Fortuna, and Manuel Antonio are reachable on asphalt. Skip Monteverde's gravel approach and the Osa.
• Rent a 4×4 and drive only in daylight. River crossings and potholes are invisible at night in the rain.
• Confirm your lodge is open before booking flights — especially on the Nicoya and Osa peninsulas.
• Pack for wet, not cold:quick-dry clothes, a real rain shell, dry bags for electronics, and closed shoes you don't mind ruining.

Better windows: when to visit instead

• February: One of the two driest months on the Pacific (2mm at Liberia), 11 hours of sun, and a gap between the Christmas peak and spring break. The most reliable month.
• Late November – early December: The Pacific dry season is established, the landscape is still green from the rains, and rates are below the Christmas surge.
• First half of May: Green-season prices, mostly sunny mornings, and the Guanacaste dust has settled. The best-value window of the year.

Click any month on the seasonality map above for the full climate detail and our verdict.