See exactly when rain will start and stop with a minute-by-minute precipitation nowcast for the next hour.
Compare today's weather with yesterday's data and track temperature trends over time.
Hourly Forecast
Daylight Hours
07:22
Sunrise
19:31
Sunset
Moon
Waxing Crescent
11:35
Moonrise
21:40
Moonset
Daily Forecast
Today
Wednesday
Thursday
Friday
Saturday
Sunday
Monday
Tuesday
Wednesday
Thursday
Air Quality Data Available
Upgrade to access real-time air quality data for San Juan.
Resources
UV Index
Humidity
Weather in San Juan today, September 15, 2026
San Juan starts September 15, 2026 under largely sunny skies, with bright spells setting the tone from the outset. Outdoor plans should enjoy long stretches of open sky as the day unfolds.
Expect highs of 38°C and cooler readings close to 26°C. Expect humidity between 30% and 72%, most humid near 23:00. A lighter breeze peaks around 17:00 near 8.1 km/h.
Later hours favour clearer intervals, as cloud stays near 48% around 23:00. The afternoon is the better half for outdoor time. Horizontal visibility holds close to 16.1 km. Sunrise is at 07:22 and sunset at 19:31, giving 12 hours 8 minutes of sunlight today.
The practical takeaway for San Juan is a bright September 15, 2026, ideal for outdoor errands before temperatures ease from about 38°C.
Frequently asked questions about weather in San Juan
How warm does it get in San Juan?
The warmest month in San Juan is August, with average high temperatures of 37°C. The average temperature during this period is around 31°C.
How cold does it get in San Juan?
The coldest month in San Juan is January, with average low temperatures of 12°C. The average temperature during this period is around 16°C.
What is the wettest time of year in San Juan?
The wettest month in San Juan is September, with an average of 81mm of precipitation.
What is the driest time of year in San Juan?
The driest month in San Juan is February, with an average of 18mm of precipitation.
