San Juan
September
Weather in San Juan for September 2026
Your guide to San Juan weather in September - trends and predictions
Heat Advisory - See hour by hour.
Until now, September 2026 in San Juan has been nearly identical to the historical average, with a temperature of 31.4 °C (showing only a slight deviation of 0 °C).
The forecast for the next days in San Juan predicts temperatures to be around 30 °C, close to the historical average.
In general, the average temperature in San Juan at the beginning of September is 31.6 °C. As the month progressed, temperatures tended to moderately fall, reaching an average of 30.9 °C by the end of September.
The climate of San Juan in September is notably wet, with an average of 14 rainy days, and a total of 225.5 mm of precipitation.
Official Weather Alert ⚠️
Temperatures
Rain 🌧️
16
Dry days
14
Rainy days
0
Snow days
31°/26°
Temperatures
21 km/h
Avg max wind
78 %
Avg humidity
San Juan Weather September
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Temperatures trend during September in San Juan
See the weather trend as well as the moving average line
September weather in San Juan day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Partly cloudy | 32° /25° | 4.2 mm | 8 | |
| 2 Sept. |  Patchy rain possible | 31° /25° | 2.6 mm | 7 | |
| 3 Sept. | Patchy rain possible | 32° /25° | 0.7 mm | 9 | |
| 4 Sept. | Partly cloudy | 32° /25° | 0.6 mm | 7 | |
| 5 Sept. |  Cloudy | 31° /26° | 5.2 mm | 6 | |
| 6 Sept. |  Overcast | 32° /25° | 0.8 mm | 6 | |
| 7 Sept. |  Heavy rain at times | 31° /25° | 11.2 mm | 7 | |
| 8 Sept. | Patchy rain possible | 31° /26° | 4.4 mm | 7 | |
| 9 Sept. | Patchy rain possible | 31° /25° | 7.4 mm | 7 | |
| 10 Sept. | Patchy rain possible | 31° /25° | 7.8 mm | 6 | |
| 11 Sept. | Light rain shower | 31° /25° | 3.2 mm | 6 | |
| 12 Sept. | Patchy rain possible | 30° /27° | 0.4 mm | 9.2 | |
| 13 Sept. | Patchy rain possible | 30° /27° | 1.6 mm | 10.6 | |
| 14 Sept. | Patchy rain possible | 30° /27° | 0.8 mm | 11.2 | |
| 15 Sept. | Patchy rain possible | 30° /27° | 0.5 mm | 6 | |
| 16 Sept. | Patchy rain possible | 31° /26° | 2.4 mm | 8 | |
| 17 Sept. | Patchy rain possible | 30° /27° | 3.7 mm | 7 | |
| 18 Sept. | Patchy rain possible | 30° /27° | 2 mm | 7 | |
| 19 Sept. | Patchy rain possible | 30° /26° | 1.2 mm | 8 | |
| 20 Sept. | Patchy rain possible | 31° /26° | 0.4 mm | 8 | |
| 21 Sept. | Patchy rain possible | 31° /26° | 0.1 mm | 8 | |
| 22 Sept. |  Sunny | 31° /27° | 0 mm | 8 | |
| 23 Sept. | Patchy rain possible | 31° /27° | 0.1 mm | 8 | |
| 24 Sept. | Patchy rain possible | 30° /27° | 0.6 mm | 8 | |
| 25 Sept. | Patchy rain possible | 30° /26° | 0.7 mm | 8 | |
| 26 Sept. | Patchy rain possible | 30° /26° | 19.6 mm | 7 | |
| 27 Sept. | Patchy rain possible | 30° /26° | 1.6 mm | 6 | |
| 28 Sept. | Patchy rain possible | 33° /25° | 2.1 mm | 7 | |
| 29 Sept. | Patchy rain possible | 31° /26° | 2 mm | 7 | |
| 30 Sept. | Patchy rain possible | 32° /26° | 0.5 mm | 7 | |
| Next | |||||
Important Notice
Our weather forecast for San Juan in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the San Juan forecast closer to your planned date for the most up-to-date weather information.
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San Juan in September - FAQ
What are the expected maximum and minimum temperatures in San Juan during September?
During September, expect a variety of temperatures with highs around 31° and lows near 26°, suitable for diverse activities and preferences.
How much rainfall should be expected in San Juan during September?
Significant rainfall exceeding 225.5 mm is expected in San Juan during September, occurring over more than 14 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in San Juan during September?
The average wind speed in San Juan during September is 21 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in San Juan
Explore the daily rainfall trends and prepare for San Juans September weather 💧
Typically, San Juan has 14 rainy days in September with a total of 225.5 mm of rainfall.
UV exposure in San Juan during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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