Last updated: August 28, 2025
In September, the average temperature in Bayan-Ulaan, Mongolia hovers around 8°C (47°F), with extremes ranging from a chilly -8°C (18°F) to a warm 25°C (78°F). Expect about 32 mm (1.2 in) of precipitation spread over 6 days, and enjoy a relatively comfortable average humidity of 68%.
In September in Bayan-Ulaan, the average temperature is 8°C (47°F). Maximums can reach 25°C (78°F) and minimums can be as low as -8°C (18°F). This range of temperatures makes Bayan-Ulaan a great destination for outdoor activities, so be sure to pack accordingly for varying weather conditions.
In Bayan-Ulaan in September, the precipitation amount is 32 mm (1.2 in), which occurs over a span of 6 days.
In Bayan-Ulaan in September, humidity is 68%. With an average temperature of 8°C (47°F), this humidity feels like a damp chill that can make outdoor excursions uncomfortable, potentially leaving travelers feeling colder than the thermometer suggests.
In Bayan-Ulaan 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 Bayan-Ulaan.
UV Risk Categories
Weather in Bayan-Ulaan varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Bayan-Ulaan, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -18°C (0°F) | 3 mm (0.1 inches) | 89% | low |
| February Weather | -15°C (6°F) | 8 mm (0.3 inches) | 81% | moderate |
| March Weather | -6°C (22°F) | 13 mm (0.5 inches) | 72% | high |
| April Weather | 2°C (35°F) | 19 mm (0.8 inches) | 69% | very high |
| May Weather | 8°C (47°F) | 25 mm (1.0 inches) | 54% | very high |
| June Weather | 14°C (57°F) | 40 mm (1.6 inches) | 60% | very high |
| July Weather | 16°C (61°F) | 86 mm (3.4 inches) | 64% | very high |
| August Weather | 13°C (56°F) | 91 mm (3.6 inches) | 65% | very high |
| September Weather | 8°C (47°F) | 32 mm (1.2 inches) | 68% | high |
| October Weather | -1°C (31°F) | 12 mm (0.5 inches) | 68% | moderate |
| November Weather | -9°C (17°F) | 6 mm (0.3 inches) | 75% | moderate |
| December Weather | -16°C (4°F) | 4 mm (0.2 inches) | 89% | low |