San José Weather in September
In San José, September brings high daytime temperatures around 24°C (75°F), with nights cooling to 16°C (61°F). This month falls within the rainy season, so expect frequent rainfall.
Rainfall in San José in September
As part of the rainy season, San José sees around 24 days of rain in September, with an average of 476 mm (19 in). Rain during the rainy season here tends to be intense rather than just persistent drizzle. Expect significant downpours.
Temperature in San José in September
September in San José brings high temperatures, with highs of 24°C (75°F) and nights around 16°C (61°F). Conditions stay fairly consistent through the month, making it easier to plan what to wear. With lows of 16°C (61°F), nights are cool. If you're out after dark, an extra layer will keep you comfortable. The cooler air at night is also great for getting a good rest.
Sunshine in San José in September
The city usually sees around 149 hours of sunlight, indicating a moderately sunny period (despite it being part of rainy season).September in San José has its charm. However, if you're seeking pleasant, dry and sunny weather, our weather planner can help you explore other destinations in the world.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Costa Rica, check out our San José's climate page.
San José Temperature in September
Min Temperature
16°C (61°F)
Max Temperature
24°C (75°F)
Chance of Rain
79%
Precipitation
476 mm (19 in)
Rainy days
24 days
Humidity
85%
Sunshine
149 hours
Percentage Sunshine
Daily Historical Temperatures
44-year average (1976-2025)
Based on our historical records, temperatures in San José typically stay consistent throughout September, with daily highs averaging around 24°C (75°F). Nights are pleasant, with lows around 18°C (64°F).
Average temperatures in September
Daily Historical Precipitation
44-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for San José in September
Browse day-by-day weather records for San José spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
San José historical weather extremes in September
Based on 29 years of weather observations in San José between 1996 and 2025, these are the recorded extremes.
- The warmest day in September was on September 7, 2009, with a maximum of 34°C (93°F).
- The coldest September day was on September 29, 2010, with a maximum of 21°C (70°F).
- The coldest night in September in San José was on September 29, 2010, with a minimum of 14°C (57°F).
- Peak precipitation in September occurred on September 27, 2019, when 164 mm (6.5 in) of precipitation was measured.
Best Places in Costa Rica in September
Find out more about the weather in Costa Rica and which places have the best travel conditions in this month. See all of Costa Rica in September →
perfect weather
pleasant
tolerable
unpleasant
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What to Wear in San José in September
For San José in September, you'll want flexible clothing. It's wise to pack cotton shirts, comfortable shorts, and a pair of jeans for cooler evenings. A light sweater or jacket is useful for air-conditioned spaces (like buses) or unexpected cool moments. Also bring a poncho, it will rain a lot! Waterproof everything you can. Sunglasses could come in handy during the sunnier parts of your trip.What To Do in San José in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Costa Rica, check out our San José's climate page.
Temperature Rainfall Sunshine Humidity
See the full San José climate overview or explore weather in Costa Rica.
