Costa Rica in September: Weather, Crowds & What to Expect

Guanacaste & Northwest Pacific (Liberia, Tamarindo, Nosara)

September is usually the rainiest month in parts of Guanacaste, with prolonged storms that can flood low-lying roads and make some remote beaches inaccessible. Surf continues to be energetic, and wildlife viewing around seasonal rivers can be rewarding if you don’t mind muddy trails. Consider staying in towns with good all-weather roads and avoid planning tight itineraries that depend on long drives.

Nicoya Peninsula & Northern Central Pacific (Santa Teresa, Montezuma, Nicoya)

September is often one of the wettest months here, with long stretches of rain that can make rural roads impassable and suspend some surf charters - but waterfalls and rivers are at their fullest. If you’re chasing wildlife, the lush fringe forests are very active, and local turtle nesting on parts of the Pacific coast intensifies at certain sites. Travel insurance, waterproof footwear, and a flexible schedule are essential this month.

Central Pacific (Manuel Antonio, Jaco, Puntarenas)

September can be one of the wettest months alongside October, with prolonged rains that can affect accessibility to remote beaches and national park trails. Water levels rise in rivers and estuaries, and boat services may be reduced during peak storm periods. Consider staying near town centers with good road connections and buy a local SIM card to monitor weather updates and transport notices.

Southern Pacific & Osa Peninsula (Uvita, Dominical, Corcovado)

September is commonly one of the wettest months on the southern Pacific coast; torrential rain can last for extended periods, making trail conditions in Corcovado hazardous and sometimes suspending boat services. If you travel now you’ll find solitude and maximum wildlife activity, but expect mud, limited road access and fewer open services. Pack a strong rainproof pack, medical kit, and choose operators with good safety reputations.

Central Valley & Highlands (San José, Alajuela, Cartago, Poás, Arenal, Monteverde)

September tends to be one of the wetter months with frequent heavy rainfall and lower visibility at mountain overlooks like Poás or Irazú; some smaller rural routes can be slowed by runoff. Despite the rain, cultural festivals and indoor attractions in San José make for good alternatives to outdoor plans. Pack a robust rain jacket, quick-dry clothing and allow extra travel time between towns.

Caribbean Coast (Puerto Viejo, Cahuita, Tortuguero)

September is often a wet month with heavy showers and occasional prolonged storms tied to the wider Atlantic hurricane season; while direct hurricane hits are rare, periods of heavy rain and strong swell can cause localized flooding. Many travelers find this a quieter time to explore with lower prices but should be ready for altered boat schedules and occasional road closures. Pack heavy-duty rain gear and buy travel insurance for peace of mind.