How warm is Costa Rica's Caribbean coast in September?

Typical highs are about 85°F and the sea is about 86°F. That is warm enough for long swims without a wetsuit.

Is there sargassum in Costa Rica's Caribbean coast in September?

In a typical year seaweed is high in September. It is usually lightest in January and July and heaviest in September and October. Landings vary a lot by year, wind and currents; Veabird's weekly sargassum report and each beach's page have the current forecast.

Is September hurricane season in Costa Rica's Caribbean coast?

September falls in the tropical storm season; the typical risk on a given day is low. It peaks in September. Travel insurance and flexible bookings help.

How crowded is Costa Rica's Caribbean coast in September?

Typically moderate, around Labor Day weekend and Mexican Independence Day. The quietest months are usually September and October.

Costa Rica's Caribbean coast in September

September is one of the weakest months for a beach trip to Costa Rica's Caribbean coast: a typical day grades C+, the 12th best of the 12 months. Expect highs near 85°F, water around 86°F and about a 89% chance of rain on a given day. Sargassum (seaweed) is usually high in September. Beaches are typically moderate (Labor Day weekend and Mexican Independence Day).

Typical dayC+12th of 12 months

Highs / water85°FSea 86°F

Rain chance89%on a given day

SeaweedHightypical year

CrowdsModerateLabor Day weekend

Storm riskLowhurricane season

Costa Rica's Caribbean coast month by month

Typical grade and high for each month. Higher is better: A+ to F.

August: C+ · September: C+ · October: C+. The best months are usually January, February and March, and the weakest are August and September.

Best beaches in Costa Rica's Caribbean coast in September

Resorts with the best typical September, and their grades for the next few days.

Beach	Typical Sep	Seaweed	This week
Umami Hotel Garden Spa	B-	Low	SatBSunBMonCTueC+WedC
Hotel Playa Bonita	B-	Moderate	SatB+SunC+MonC+TueB-WedC+
Hotel Palace	B-	Moderate	SatB+SunB-MonC+TueB-WedB-
Hotel Playa Westfalia	B-	Moderate	SatB+SunBMonC+TueC+WedC+
Goddess Garden Resort	B-	Moderate	SatB+SunBMonC+TueC+WedC+
Coco Loco Lodge	B-	Low	SatBSunBMonC-TueC+WedC
Casa Grande Eco Lodge at Pacuare Reserve	B-	Moderate	SatB+SunC+MonC+TueC+WedC+
Ocean View Lodge	B-	Low	SatBSunBMonCTueC+WedC

Grades for the next few days from Veabird's beach forecast, updated Oct 3, 18:00 UTC. Higher is better: A+ to F.

Better beach options in September

Elsewhere in Central & South America, Panama's Pacific beaches (B), Roatán & the Bay Islands (B) and Belize (B) usually grade higher in September. Further afield: Maui (A), Oʻahu (A) and Kauaʻi (A). Every destination in September.

Questions

Is September a good time to visit Costa Rica's Caribbean coast?: September is one of the weakest months for a beach trip to Costa Rica's Caribbean coast: a typical day grades C+, the 12th best of the 12 months. Expect highs near 85°F, water around 86°F and about a 89% chance of rain on a given day. Sargassum (seaweed) is usually high in September. Beaches are typically moderate (Labor Day weekend and Mexican Independence Day).
How warm is Costa Rica's Caribbean coast in September?: Typical highs are about 85°F and the sea is about 86°F. That is warm enough for long swims without a wetsuit.
Is there sargassum in Costa Rica's Caribbean coast in September?: In a typical year seaweed is high in September. It is usually lightest in January and July and heaviest in September and October. Landings vary a lot by year, wind and currents; Veabird's weekly sargassum report and each beach's page have the current forecast.
Is September hurricane season in Costa Rica's Caribbean coast?: September falls in the tropical storm season; the typical risk on a given day is low. It peaks in September. Travel insurance and flexible bookings help.
How crowded is Costa Rica's Caribbean coast in September?: Typically moderate, around Labor Day weekend and Mexican Independence Day. The quietest months are usually September and October.

Plan it

Typical-month numbers from Veabird's year-ahead outlook for the 41 resorts here (median resort): 6 years of ERA5 climate normals, the seasonal pattern of the Atlantic sargassum belt, holiday crowd calendars and historical storm tracks. Any given year can differ; check the 16-day forecast before you go.