Costa Rica
Best Time to Visit Osa
Osa, Costa Rica's southernmost region, is a tropical paradise with two main seasons: the dry season (December to April) and the rainy season (May to November). The dry season is ideal for wildlife spotting and outdoor activities, while the rainy season is characterised by lush green landscapes and fewer tourists. Visiting between December and April is generally more comfortable, but the region is more crowded during this time.
✦ Visit Osa between December and February for the best combination of weather and crowd levels.
✅ Best months
December, January, and February are the ideal months to visit Osa, with warm temperatures (average highs around 27°C/81°F), minimal rainfall, and manageable crowds.
🔥 Peak season
June is the peak month, driven by the summer solstice and the start of the whale migration. Hotel prices increase by up to 20% during this time, and crowds are at their highest due to the region's popularity with eco-tourists. The Osa Peninsula's lowland rainforests and coastal areas are particularly busy during this period.
💷 Shoulder (best value)
April and May are the best budget shoulder months, offering discounts of up to 15% on accommodation and fewer crowds. The weather is still pleasant, with average highs around 28°C (82°F), and the region's lush landscapes are at their most vibrant after the dry season.
🌙 Quietest & cheapest
The quietest and cheapest period is from September to November, with prices dropping by up to 30% compared to the peak season. However, this time of year is characterised by heavy rainfall and occasional flooding, which may impact outdoor activities.
Osa season by season
Spring (Mar–May)
Weather: Temperatures range from 22°C (72°F) to 28°C (82°F); occasional short rain showers
Crowds: Low
Ideal for wildlife spotting and outdoor activities
Summer (Jun–Aug)
Weather: Hot and humid, with frequent rain showers and temperatures around 30°C (86°F)
Crowds: High
Whale migration and summer solstice draw large crowds
Autumn (Sep–Nov)
Weather: Heavy rainfall and occasional flooding, with temperatures ranging from 20°C (68°F) to 25°C (77°F)
Crowds: Low
Best time for birdwatching and turtle nesting
Winter (Dec–Feb)
Weather: Dry and sunny, with temperatures around 27°C (81°F) and occasional cooler nights
Crowds: Medium to High
Best time for hiking and exploring the region's national parks
🎭 Events worth timing a trip around
The Osa Peninsula's annual 'Festival de Jazz del Osa' takes place in May, featuring live music performances and cultural events. The whale migration, which peaks in June, is another major draw, with humpback whales passing through the region's coastal waters.
🧳 What to pack
Don't forget to pack lightweight, quick-drying clothing and a waterproof jacket, as the region's tropical climate is prone to sudden rain showers.
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Researched & reviewed by the TripSage editorial team · Updated July 2026.