Last updated: June 24, 2025
In Castlewood, United States, the average temperature in September is a mild 17°C (63°F). Visitors can expect a range from a brisk 2°C (35°F) to a warm 32°C (90°F). Be prepared for some rain, as 88 mm (3.5 in) of precipitation typically falls over 9 days. With an average humidity of 82%, the atmosphere can feel quite damp, making it essential to pack appropriately for both warmth and moisture.
In September in Castlewood, the average temperature is 17°C (63°F). Maximums can reach 32°C (90°F) and minimums can be as low as 2°C (35°F). This makes it a great time for travelers to experience a comfortable climate while enjoying the various outdoor activities that Castlewood has to offer.
In Castlewood in September, the precipitation amount is 88 mm (3.5 in) over the course of 9 days.
In Castlewood in September, humidity is 82%. With an average temperature of 17°C (63°F), this humidity feels like a warm blanket wrapping around you—comfortable yet heavy, making outdoor activities more taxing and requiring frequent breaks for hydration.
In Castlewood in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Castlewood.
UV Risk Categories
Weather in Castlewood varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Castlewood, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -10°C (15°F) | 22 mm (0.9 inches) | 85% | moderate |
| February Weather | -10°C (15°F) | 18 mm (0.7 inches) | 89% | moderate |
| March Weather | -1°C (31°F) | 50 mm (2.0 inches) | 81% | high |
| April Weather | 5°C (41°F) | 68 mm (2.7 inches) | 82% | very high |
| May Weather | 13°C (56°F) | 89 mm (3.5 inches) | 76% | very high |
| June Weather | 21°C (70°F) | 79 mm (3.1 inches) | 81% | very high |
| July Weather | 23°C (73°F) | 83 mm (3.3 inches) | 82% | very high |
| August Weather | 21°C (70°F) | 109 mm (4.3 inches) | 83% | very high |
| September Weather | 17°C (63°F) | 88 mm (3.5 inches) | 82% | very high |
| October Weather | 7°C (46°F) | 77 mm (3.0 inches) | 82% | moderate |
| November Weather | 0°C (33°F) | 26 mm (1.0 inches) | 87% | moderate |
| December Weather | -5°C (24°F) | 31 mm (1.2 inches) | 84% | low |