Last updated: June 24, 2025
In September, the average temperature in Roseau, United States is a mild 14°C (57°F). However, temperatures can swing dramatically, with a minimum of -5°C (23°F) and a maximum reaching 31°C (87°F). Be prepared for some wet days, as you'll likely encounter 80 mm (3.1 in) of precipitation over approximately 10 days. Keep in mind that the average humidity is relatively high at 75%, adding to the overall climatic experience.
In September in Roseau, the average temperature is 14°C (57°F). Maximum temperatures can reach 31°C (87°F), while minimum temperatures can dip as low as -5°C (23°F). Travelers should be prepared for a wide range of temperatures, so packing layers is essential.
In Roseau in September, the total precipitation amount is 80 mm (3.1 in) over a period of 10 days.
In Roseau in September, humidity is 75%. With an average temperature of 14°C (57°F), this humidity feels like a damp blanket enveloping you, making outdoor activities somewhat uncomfortable and travel a bit sluggish, as the air feels heavy and the heat lingers close to your skin.
In Roseau in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Roseau.
UV Risk Categories
Weather in Roseau varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Roseau, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -14°C (8°F) | 20 mm (0.8 inches) | 94% | low |
| February Weather | -15°C (6°F) | 22 mm (0.9 inches) | 91% | moderate |
| March Weather | -4°C (25°F) | 23 mm (0.9 inches) | 90% | moderate |
| April Weather | 3°C (37°F) | 38 mm (1.5 inches) | 81% | high |
| May Weather | 12°C (54°F) | 60 mm (2.4 inches) | 74% | very high |
| June Weather | 19°C (66°F) | 80 mm (3.2 inches) | 75% | very high |
| July Weather | 21°C (70°F) | 74 mm (2.9 inches) | 74% | very high |
| August Weather | 19°C (66°F) | 74 mm (2.9 inches) | 77% | very high |
| September Weather | 14°C (57°F) | 80 mm (3.1 inches) | 75% | high |
| October Weather | 5°C (42°F) | 82 mm (3.2 inches) | 78% | moderate |
| November Weather | -4°C (24°F) | 30 mm (1.2 inches) | 87% | low |
| December Weather | -10°C (14°F) | 34 mm (1.3 inches) | 93% | low |